Okay, so you're half my age and in your first relationship, nothing wrong with that.
I will say though, that in order to keep a relationship from going stale, it couldn't hurt to add a little spice. Which starts with communication and being receptive to your partner's fantasies and dislikes. Kind of how Jamie is pretty open about her kink to watch her BF have sex. I'm not saying you have to jump on top of every one of her fantasies, or she yours, but by exploring that together, you might find yourself open to more kinks than you imagined.
Also as you grow older you might grow more curious about what else there is to explore. I was pretty vanilla myself at your age (had sex with only 2 girls at that time, and not simultaneously) and if you told me then, I'd be into feet or dating a virtual transgender person when I'm older, I'd probably laugh. And punch you. I was quite the intolerant asshole at that age. Luckily, I'm no longer as intolerant. Still an asshole though.
But like I said, Variety is the spice of life, and this isn't the kind of site or forum for kink-shaming, and by playing outsie of your comfort zone you might discover an interest you never thought you had before.