It's a bit mature, sure, but actually, it probably works really well for your figure. Good for you for knowing what works on you. Everyone wants to wear a bikini, but bikinis do not work on EVERY figure. So this is a good choice, I think. I don't know what your skin tone or color is... if you have dark skin like me, I'd say stay away from black swimsuits. They just don't look very interesting. But if you're lighter skinned, definitely go for black, as it slims you somewhat & hides certain flaws (anything YOU consider a flaw, that is).
Since you said you like certain kinds of tankinis, there's a few here you might like- http://store.alloy.com/browse.do?categoryID=2539&sidenavTrack=swim.top.tankinis&incmpid=LNavswim.top.tankinis