I do hope I become a spirit and can go anywhere in the universe or on Earth if I want to. It would be nice to be with the ones you loved during life but to be honest who really knows?
It can be daunting to ponder on but don't bother with it, we may be young now and full of energy and enjoying life, doing what we love (or maybe not), as life progresses and you age, your mind also ages too. You will witness the passing of loved ones such as relatives and friends, and also notice well known people such as those in the media who are from this era pass away and will gradually come to terms with what you must eventually have to face, until the time when you literally become so old and carefree (tired, if you must) you will not actually worry about it too much I guess and hopefully pass away in peace.
You could on the other hand get dementia and be none the wiser I guess.
Life is a long battle with a lot of highs and lows, just bear with it, its' like the ultimate test of tests that anyone or anything has to endure, just be happy to live, and do stop worrying, since when you die you will not have the energy left to (literally), so don't waste your life being scared of the inevitable, be thankful you have a life at all, and do a lot of things that you want to, go places, see the world, you might even meet that special someone out there, so when you do get old you don't have to regret what you could have done when you had the chance.