Is it possible to ask offers of admission to extend the deadline? I was offered an admission of offer (math) today and I found out that I have till Feb 15th to accept the offer. Most schools in my country (Canada) actually send out offers during Feb, and there is a low probability that I will get an offer then, is it okay to ask schools to extend the offer date?

Note I am Canadian. Schools in Canada don't generally give out scholarships until NSERC hands out theirs. My school gives entrance scholarships after you get NSERC, in which case, they announce it in March, wayyy past the deadline.
Yes, it's definitely okay to ask.  They're certainly not going to rescind the offer because you ask for more time.  Depending on the school, their applicant pool, how bad they want you, and (probably) how rigid their administrative structure is, they may grant or refuse your request.

You should, of course, word your request very politely and recognize that they have the right to say "no".