BEING AFRAID OF TIME

I just turned eighteen a few days ago, and since then a fear has appeared in my mind: do time pass too fast and am I really enjoying every moment like I have to?
I'm starting to realize time is relative and that the more you live, the more you think time passes really fast, at least in my case. I start remembering my childhood and sometimes I'm surprised because it's actually difficult to remember some things that I know I lived, and above all sometimes I don't remember thing that just happened eigh or ten years ago, so I'm arriving to a conclusion: when I'll be like 40 or 50, will I remember this moment, sitting at my desk, writing this post after a fun weekend enjoyed with my friends, I really won't remember all the fantastic moments I'm going through in this years?
That's the main reason why I'm scared, I'm afraid because I'm scared I won't remember well the people that nowadays is one of the best aspects of my life: my friends. I spend so much time with them, we share so much, laughs, tears, happiness, sadness, and maybe in a few years I'll just remember their names, their faces and little more. Maybe people will think this is silly, but it's a question that matters to me, because I'd truly want to be able to remember ALL of the moments that produce me a smile, because after all this is the more important thing for me in life, to be Happy and to be able to revive and to remember all the important moments of my life, the ones that have made me happy.