I say give the girl a shower! I think it's great that she has a mom who supports her and is excited about the baby! My gf had her first child when she was 15 (25 years ago!) and she didn't really have anyone to support her then, even her hubby was only lukewarm about the idea. Personally, I don't think it should matter what's "acceptable" these days... I reckon if the idea feels good, run with it!

Congrats, btw! Everyone is getting preggers but me... *sigh* Be sure to post pics when the little one pops out!