Is it Childish for a grownup boy to keep a memory scrapbook?

Hello, I'd love to keep my memories alive, some sweet moments in my life must be remembered every while. I've many awesome memories of vacation and birthdays spend with my family and friends. but as days pes, i ought to forget about it gradually..i don't wish to happen like that, so i've decided to keep a memory scrapbook. BUT, My granny and my friends are saying..that I am not a child to keep scrapbooks"...CAN A GROWNUP TEEN KEEP IT??