How likely am I to get into an Ivy league college like Standford, MIT, Harvard, etc?

Ok, so I'm 15 and I've been wondering. I've completed about 150 hrs. of community service with one of them really inspiring me (which i prbly will write on my essays) (i plan to do about 500 or more by the end of hs). i am in 3 ap cles, and i will eventualy be taking all ap cles in 11th and 12 grade. I am very good at the saxaphone (placed in 10-12 gr band when in 9th grade), and i have recieved a 3/4 (excellent) on my instrument solo at sections and a 4/4 (superior-go to state) on a quartet. i plan to go to state with our whole band sometime in the next 3 yrs and plan on going with at least a duo, trio or solo. I have a gpa of 3.97 for my whole freshman year. I also plan on taking the act test with writing and doing well (29 or higher). I will be on the knowledge bowl next year (10-12 gr) and will be on student council (11-12 gr)....but please help me-i am soooooo nervous because i wanna get into a really nice college but am scared about acceptance and financial...i know....i shouldnt worry about it already but i do... :s