I don't think it really matters what personality you are, but why you are doing it. We all have feelings and express them in our own way, but it's our intentions that we generally draw the connection. If a girl wants attention and is insecure about herself, I imagine sex would be less meaningful. If she genuinely sees something more in you than others, it's a little more meaningful, but only in a sexually stimulating way.
I was raised a strong Christian, so I was taught the only meaningful sex is when you're in marriage. I think differently now because love is not measured by a ring. If you and your partner feel comfortable enough, and you both want to continue a meaningful relationship, then I believe it's not sin.
I only speak wisdom cuz i is a virgin...