Emotional Maturity

So my boyfriend is 6 years older than me, I'm 18 and he's 24. The gap isn't really huge, but because I'm so young I feel like he's a lot farther ahead of me. I'm a total crybaby and I tend to be somewhat childish when it comes to my feelings. He says these things don't bother him, but I feel like it's frustrating for him that I'm not as familiar with myself as he is. I'm very mature for my age, and that's always helped since I have a thing for older men, but he seems to be too. How can I be sure that I'm enough for him?