Silly Option? It's an awesome option.... who would not want to be young forever?
and as far as watching your loved ones go is concerned... what makes you think you won't see them leave if you are mortal. Life can always change for worse... you have to learn to make the best out of it.
Anyhow, I am not sure if I would like to be immortal but it sounds like a pretty good option. Given a choice, I might just say yes

.... age 25 (Next year I will be even more awesome)