Every Saturday morning for the past two months my alarm sounded at 5.45am. By 7.15am I was running along Seafield Road in Edinburgh, often in the half light and wind. At that point each Saturday morning I asked myself, “What on earth am I doing?” While friends were still sleeping, I was admiring a sunrise over the Firth of Forth in Portobello or listening to the clap of the waves against the promenade.

The sunrise and the sea provided only temporary distractions from the task at hand. When the sun had come up and the waves were nowhere near, there was nothing to distract me from the twinge in my knee, from wondering where the nearest public toilets were, and again asking myself - “Why am I doing this?” My question was answered on Monday 26th October, when I ran over the start line of the Dublin Marathon.

“Why the Dublin Marathon?” people asked. I’ve lived in Edinburgh for two and a half years. Though Edinburgh is a majestic, beautiful city and my home for now, I felt strongly that if I was going to undertake something as challenging as a marathon, I would need it to be somewhere familiar. I needed it to be in Ireland.

My best friend picked me up at Dublin Airport the Saturday before, and we went directly to the marathon expo at the RDS. I was running the marathon in aid of Focus Ireland, but even with the good cause firmly in mind, I couldn't stop comparing myself to the sculpted bodies I saw emerging from the RDS, and wondering if I was up to this challenge. These people looked like athletes. Look at their calves!

But my nerves dissolved into excitement. I picked up my number with my name on it - “All the best Mary”. I was surrounded by so much positivity, and many good wishes from volunteers who I had never met before. My anxieties faded away.

On Sunday morning however, I woke up with the fear. But this wasn’t your average bank holiday Sunday morning fear. This fear was not drink related.

I met friends for lunch, a welcome distraction. I walked out again to the RDS where I was meeting fellow runners, my auntie Jean and friends from my hometown of Dunmore in Galway, Peter and Joan. Yet again, it was the volunteers who surprised me at the RDS with their joviality and warmth. It was as if they could see the fear in my face and knew they had to do something about it. Being at the RDS confirmed for me that I had been wise in my choice to come back to Dublin - I knew there was nowhere else I could have run my first marathon.

Over dinner, myself and my three companions, who had all run marathons before, shared stories of our training experiences. Afterwards, we walked the 800 metres from our hotel to the finish line. “Visualise this line, keep it in your minds, see yourself here tomorrow,” Jean advised. As we walked back to the hotel, I thought to myself - the next time you pass this pub, this house, this tree...you will be almost finished.

The morning of the marathon was the most calm I had been in two months. There was a buzz in the air at breakfast. Everyone in the room was a runner. I felt like I knew everyone. We had a shared vision for that day. A man asked me if I had managed to eat anything. I must have looked as nervous as I felt.

I spent 20 minutes alone in the hotel room, getting focused. I watched ten minutes of Those Were the Days on TV3 and it was the showing Riverdance at the Eurovision. The familiarity of that music made me feel even better.

I walked with Joan and Peter to the starting line. Joan and Peter were running together, and it wasn’t my intention to stay with them, but for whatever reason, we ended up together. If I couldn’t see them near me, I naturally found myself turning my head looking for them, and I could see they were doing the same.

From the moment I crossed the line, I was happy. The atmosphere was incomparable to anything I had ever experienced before. The first two miles flew by.

It would be hard to equal the feeling I had when I first saw my first crew of supporters in the Phoenix Park. They were jumping and screaming, and I was as excited as they were. My father sprinted 100 metres ahead of me in order to take a photo. A best friend from college and her boyfriend met me at mile 11 with water and an orange.

Between mile 11 and mile 19 I didn’t see anybody I knew. But luckily, I was in one of the friendliest cities in the world. Random strangers were cheering me on. Every mile provided me with something to feel positive about - people with signs reading “Go random stranger go!” or a man blasting “Dancing Queen” by Abba from the boot of his car.

My friend met me at mile 19 where things were starting to feel tough. She ran beside me and I remember clutching her hand tightly, not really wanting to let go. I hit mile 20 and allowed myself to feel like I was going to finish it.

When I reached the top of Heartbreak Hill a friend from college was standing with a sign with my name on it - and I couldn’t control my emotions as I jumped and hugged her, before cantering on. My emotions were tested again when another friend who had been living in Australia for two years was running beside me, baby bump and all.

Miles 23 to 25 were by far the toughest. But at least at that stage, I had stopped doubting, I knew I was going to finish. And soon, I was at mile 25.

When I passed the RDS I got a lump in my throat. I was going to do it. With 600m to go I spotted my parents, which made me want to cry. Both of them shouting “Come on, you’re there, this is it, you’ve done it.” Just before the finish line I spotted more of my support squad, cheering me on to the end.

As I crossed the finish I looked up to the clock. I had run faster than I had anticipated but that did not matter. I had just finished a marathon. The answer to my doubting questions had been answered. My uncle John, a seasoned marathon runner, had texted me the night before wishing me luck. He said that the feeling when I crossed the line was one I would never forget. And he was right. I am 25, and it is probably one of the best feelings I’ve ever had in my life so far.

When you experience a high as great as the one I got from finishing the marathon, there is only one way to go. I was emotionally drained by Tuesday afternoon. Two and a half years living abroad, I have become accustomed to goodbyes. But this time, I didn’t want to leave my parents; I wanted to go home to Galway with them so we could continue to bask in the marathon glow.

I didn’t want to leave Dublin, the city that had given me so much the day before. I said a teary goodbye to Mum, Dad and Dublin. I sat alone in Butler’s café in the airport and silently sobbed as I read The Irish Times marathon coverage.

Those dramatic, over the top feelings have ebbed away by now, but the memories of the day have not. A week later, I am just about down from the high. I can still hear the Dublin accents shouting “Go on Mary you’re almost home!”