I think so. I went from 76mph as 17yo High School Sr. to 81 as a 19 year old Freshman and then 88 mph by sophomore season. (and back then throwing 90 was a Wow type of thing)
But I had a body frame that could put on 25 lbs of muscle from 6'3" 165 to 6'3 190 over that 2 1/2 year period.
If you are maxed out in size, flexibility, and mechanics (and I can't imagine you are at 65mph) then that big a gain is probably not possible, but if your still developing, sure why not.