I've been inactive for 3 years (like zuko725 said, it's not 13, but I understand a little) and I came on here as well before I attended my ward. The advice I got here was effectively to just go and act like I've always gone! It's really gone well for two weeks in a row. I was terribly nervous the first Sunday, but it was lovely.
However, besides simply getting there, I would also suggest a couple other things. First, I scheduled an appointment with the Bishop to tell him a little about my history. This way, I've made myself known to the Bishop and he knows my history of inactivity, just in case I begin to slip away. I would suggest that you do the same as well. Bishops are called by revelation, so his counsel to you can be inspired. Which leads to my next piece of advice: fasting before you go to Church. I am going to fast before my appointment with the Bishop (it's this Sunday). My fast will be for the courage to actually go to the appointment (!) and also that my Bishop might have the Spirit with him to give me the guidance I need.
Next, I cannot stress this enough, do the "ABCs" of LDS activity. This has helped me a lot. I go to all my meetings and also try to attend any extra ward activities. In making an effort to become known in my ward, I will build a support system that will keep me on the straight and narrow.
Last, read your scriptures and pray daily. Of all the things, this one is probably what has made the biggest difference. I am rebuilding my relationship with Christ and nothing draws me closer to Him than reading the scriptures and praying. At times I don't feel anything, but I know that obedience sometimes precedes spiritual experiences.
I hope that helps! I immediately related to your story since I listened to YouTube videos of hymns before signing onto this site as well! I would recommend BYU's "Come Thou Font" www DOT youtube DOT com/watch?v=mUhU0HgTq94