I understand the anxiety. I'm a musician and I had that sort of anxiety at school but these days it's just not there at all because I gigged so much after I left school. It does get easier and especially when you find your peer group you'll find people can be pretty supportive just like Bill has talked about on his podcast when he started comedy. I went to music college which was a big risk but I'm teaching a lot and doing live work now and if I decide I want to move away from music I'll re train but, honestly, your degree isn't as much of a risk as you might think if you go to a respected school. Theatre is not Hollywood and is still pretty traditional, especially in England, so a good education is pretty necessary. I didn't go to Guildhall or Berklee or anything and that will always make certain music jobs harder to reach if I were to go for them because their graduates have the weight of that institution behind them and the connections they've made from going there. Best thing to do would be to start right away getting involved in local theatre and latch yourself on to people who are better than you and willing to give good advice. Look up the best schools for what you want to do and what you need to do to be a successful applicant. I'd also suggest you look up what other careers there are related to a performing arts degree because if you do have to "compromise" you want to make sure those are options you can live with. Performing arts is fairly risky but I know people with English lit or modern history degrees working dead end jobs. I also have a friend who was on my music course and is retraining to be a lawyer because he decided entertainment law was what he wanted to pursue and that came about because he went to music school. Bottom line is if you love the theatre you should get involved locally and I guarantee people will help you bed in, from there you can ask people better informed advice on what direction to take. You're young man, I'm 25 and I'd love to be 18 again and I'm sure someone 30 would say the same to me. You have time on your side whatever you chose to do.