Im Afraid Of The Future? Lifes Moving By Too Fast? Help!?

Ok so im 16 and am in grade 11 (first semester). Basically my issue is im afraid of the future. I wish time moved slower! The past 10 years, lifes been great for me! Public school was terrific. But I think whats happening now is ive just woken up and smelled the roses and figured out that this is it. Im in grade 11 and in only 2 years (im planning on taking grade 13) Im going to be going somewhere completely different, separated from my family and school friends! And this scares me. I love my family with a pion, as everyone should, but my parents are very loving and easy going, I love my house and being able to see my friends everyday at school. And I can't imagine not living without them. I still don't know what I want to work as so that may be contributing. But I get sad when I think about memories from my years in public school, not knowing thatI had 10 more years and I should cherrish them. And I wish I could go back so badly! I dont think im ready for whats about to happen. Ive been with my clmates ever since grade 2 so all of us splitting off gets me sad. I'm tired of being in this mentality of doom and saddness and I wish I could be happy about everything, but theres nothing I can do. Time is time and eventually ill be moving out and starting my own life, but I dont really want to, Id love to stay with my family and friends forever. Any tips to ge tme out of this mentality woul dbe great! An dplease no snarky comments. Im serious. Thank you!!!