Persue a career in acting?

I thought i wanted to be a musician, i play guitar and i sing and have been playing the guitar for 4 years with lessons and singing for 2 without lessons but i just don't think im good enough so then i changed interests and thought i wanted to be a director/producer and started a btec course in media at the brit school for performing arts and technology but I've recently started to gain an interest in acting, and i think i want to take it as far as I can, I've been acting for long as I can remember but have only acted in small performances when I was in primary school, I'm now 15 but haven't done any performances since, I was thinking of auditioning for a place in the national theatre which is an acting group and then eventually (after doing alot of performances) finding an agent but I'm not to sure if this is the right path to choose, please help me?!?