Your eye power
needs to be stable before you can undergo LASIK. By what you have told me, your eye power has not stabilised yet. The eye power usually stabilises by the age of 18-20yrs (although it may take longer)
Also LASIK surgery requires other investigations as well, and there are plenty of other criteria which decide if you are eligible to undergo the procedure; not only eye power stabilisation.
I would advice you to consult an ophthalmologist, and talk to him/her regarding you concerns. Get all the necessary tests done and also after examining you the doctor would be able to tell you if you can get LASIK done or not.