I want to know about my gf's sexual past

Is it normal to want to know about my girlfriends sexual past? We've been together for 2 years now and we're inseparable, we like the same things, enjoy the same actives and just generally enjoy being in one another's company. She was my first and she's always told me that she wishes I was hers, I've always been worried if I'm good enough sexually and she tells me I'm more than adequate and that's she's honestly never came before me which feels pretty good you know, who doesn't like being the best at something? Anyway, she's lied to me before about how many people she's slept with and finding that out kinda hurt, I know it shouldn't matter because it's the past but i feel like it matters to me, she lost her virginity at a young age and has slept with some people the first time they met, I'm a proper kind of guy and to me that's a bit slutty. We were at a party one time and she was bragging about where she'd slept with the guy and that made me feel like shit you know, I was right there and at that point we'd never even slept together. I love her to bits but for a while I just couldn't stop thinking about what I knew she'd done and where she'd done it, it made me feel inadequate and just generally shitty. Anyway, is it normal for me to want to know everything that she's done? Even though i know finding out the answers will probably hurt me, I just can't help the urge to know more.