Why am i uncomfortable around older girls?

im a 24 year old guy and have always dated younger girls. older ones make me uncomfortable for some reason and i've always hated my older sister's friends. i remember when i was about 6 or 7 some of them looking down on me and being condescending to me, but i would hope i've gotten over that by now. if any older girl shows interest in me i look away and talk to someone younger. the fact that they're more mature and developed drives me away.