You'll have such a blast! I traveled solo in Ireland and I felt perfectly safe. I just utilized common sense while I was out and about--being aware of my surroundings, I didn't get drunk or anywhere near it. The Cliffs of Moher was the only place out there that I was hiking alone for part of it. As I said above, I met a young woman my age at the bus stop who was going to the Cliffs as well. We hit it off and we hiked most of the day together. She had to leave earlier than me, so I hiked alone the remainder of the way to the tip area (the far end that you can see from the visitor's center) which was about a 2-2.5 hour trek total from the visitor center. And I hiked alone back and was just fine. Didn't run into many people that far out.

One thing just to be aware of if you visit the Cliffs is to make sure that it will be a nice sunny day, and not too windy. It can be really foggy there and if it is, you won't see anything at all. There were a couple girls at my hostel who went the day before and their experience was literally just seeing a sheet of white. Nothing else. If it is super windy, they won't allow anyone to visit, as many people have been blown over the cliff's edge by the sudden wind gusts that occur. I kept a healthy distance from the edge of the Cliffs.

In terms of pubs, I didn't go to many in Ireland since I was on a tight budget by that point. But I would just say to make sure that you are able to still take care of yourself. Personally, I never had more than two drinks when I was out away from my hostel, and as I do here, I didn't lose sight of my drink. Some hostels have bars in them, and those are fun because you can meet your bunkmates and connect with other travelers.

I was an early riser when I was traveling so usually by the time it got dark, I was clonked out in bed already lol