Grats on the guitar! I have played for a long time and the only thing I can say is don't over-think what it's sounding like. Try to keep up with a backing track, very inexpensive and more helpful IMHO than a metronome. It gives structure as well as timing to your playing. Don't worry about the mistakes so much(most people will think you planned it like that) just press on with the piece and get back in, it will come with practice and patience with yourself, remember guitar is a lifetime endeavor.