shoul I continue my phanom after the opera fanfic? and what couyld I improve? plz tell me!

Well, to be honest I haven't been reading it, but I'm just now giving a look through chapter 3.
Remember to capatalize your words at the beginning of a sentence. You need to be careful to make sure that all of your sentences make sense. Example, "It was finally a prove of what her uncle always told her".
As a creative note, you may want to think about coming up with your own last name, or using a different source material. Destler has been done to death, and as no last name was ever given in the original novel, you might want to feel free to let yourself add a touch of your own imagination into the story in this way. This is entirely my opinion, but it would help to make your work stand out a bit, I think.
What books? If you mean Gaston's notes and the personal letters he obtained, you should say so. Also, (and this may have been explained in an earlier chapter, please forgive me if it was) how OLD is Erik meant to be in this? Leroux died in 1927, a good 17 years after he wrote Phantom. He also mentions that the action of the novel itself goes back up to 20 years from that point, and it's hinted that Erik was at least middle aged during that time as well. So if you assume 40+20+17=77. That's a VERY old Opera Ghost. You might want to rethink your numbers.
Consider changing the first sentence in the fourth paragraph. It reads oddly. Your spelling also needs work. What is a "put"?
Take your time and write out complete thoughts. Your narrative seems to become a bit difficult to follow toward the end of the chapter. You might also want to watch out for your character sounding too much like a Mary Sue. Jack of all trades+OMG so dramatic childhood!+I swear to GOD if Erik wakes up and declares her to randomly be a better singer than Christine I will smack you= MARY SUE!

Apologies if this is rather brutal, but at least Phanwank didn't get ahold of it first.