My 10 months old is not crawling yet!?

my son is 10 months old as well and still wont crawl. idk why. he shows no interest what so ever. he still can't wave. he did say "kitty" the other day. his first word :D and he drinks from a sippy cup. tries to walk. his doctor said she wants to wait until he's 15 months old and then go from there to see if he's got some kind of muscle problem. he still wont pull up from laying down to a sitting position. he can sit for ever just fine. it's just once he falls over, he can't get back to a sitting position. she thinks his legs are fine though. said he's probably just lazy lol best of luck to you!