Everyone seems to give the same advice regarding the friendzone. "Just man up, tell her and cope with the sh*t that comes with it."

This is alright to do in some cases, but if you start developing feelings towards someone who has been your bestfriend for the last 5 years, is it really worth giving it a shot and possibly lose someone that has always been there for you?

I've had girlfriends that were my bestfriend at the time but it was quite the battle and it was before my 20's and I realise that you come to an age where everything's settled and there isn't much you can do. What are your thoughts on the subject of trying to step up/risking the best friend zone?

Edit: spelling.