Is it normal for big boobs to be so perky?

Okay so I'm 15 and I'm a DD cup but they like, dont go down at all. Haha. I mean i know almost all girls want perkier boobs, but is it possible for them to be TOO perfect and rounded out? I always wear a bra, but at night when I'm in pjs it looks like I have a pushup bra on because my boobs are perfectly round and perky. Its weird. Is that a bad thing?