Its my mistake, so don't say sorry

What's the point of having a best friend when your going to loose her/him. Huh? I keep telling myself no more best friend its just going to hurt you at the end but no I, a stupid 15 year old girl decided to take the risk and I am pretty sure its going to end me getting hurt. When I know everything than why do it, cause my stupid myself thinks that things can change and that everything deserves a chance. Point is I am stupid for believing that I can ever have a best friend.