Orgasm question

I had my first orgasm at a very young age. Like probably 7 or 8 (my friend said to hump a pillow, weird stuff for an 8yr old I get it) HOWEVER it's really difficult to orgasm with a partner. My ex NEVER got me to orgasm! Maybe he was just bad at sex? I mean we were both each others firsts and we only had sex like five times. I'm just worried I'll never orgasm with my current girlfriend. She tries so hard! Help, what can I do?