As a first time mom, I have no idea if she's peeing too much

At 14 months she is not walking yet and so she does sit quite often. I think that's when we have the issues (which are daily). Like in the grocery cart she soaked through and often soaks through in her jumper. It doesn't always fill the diaper but lands in a certain area like the front. Right now I'm in a battle over her sleeping in the jumper. I will sneak her into her bed and hubby will sneak her back into the jumper. She had a booger choking problem in the past and he feels this way she wont choke, but she's past that now. She is always wet after a night's sleeping in it.
I have noticed a few times the ruffle in the cracks. She acts like a crocodile with a prey when changing her. She's incredibly strong and just rolls non stop and it's a huge struggle to get them on. I've tried putting them on backwards or her standing. I give her toys, blankies, things to look at but she just rolls and rolls and rolls. I've held her still and she'll contort her body so it's almost rolled anyway.
She's small for her age 20 pounds, though I should reweigh her. She really slowed down at 18 pounds and only gains about .5-1 pound a month. The pampers fit really well, walmart brand is very snug. Maybe it's time to try a size 4 now. 12m fits her still and 18m clothes fall off of her. She has a very tiny butt :P (6wpre)
I don't actually time her changes, I'm just guessing. At 14 months she should be sleeping a bit more but lately she's been waking up every 4 hours to eat.
I ordered the gerber peva pants size 9-12 and I'll get a bigger size diaper when I run out. I kind of like the idea of cloth diaper outside too. thanks for all the ideas
