Found a weakness in a game I won

nice

I wouldn't say that at amature level a pawn lose is a blunder.

When you mentioned that half open files they were actually completely open,with none of your pieces in it and only the two back ranks cant be reached.

Assumming you don't mind my comments...

Move 10. 0-0 seems weak to me, and your reasoning; "It's now or never to castle" is flawed. You could certainly have waited until you had developed a few more pieces.

14. Bb3 - I don't understand why you pin the f pawn... I feel as though you should have developed your dark-squared bishop by now, as well as that Queenside knight. Perhaps moving c3 with a thought towards d4 would work better.

17. Nc3 - You already get what happened there, I figure d3 would be a good choice there.

Past that, there isn't much to say. I'm not sure about the Bishop placement on d6, but I have no reason to call it bad.

All in all, congratulations on the win.