I wish I could get her to potty train..

I so wish I could get Baby T to potty train. We sit her up on the potty and ask her to try to go and she doesn't. Yet, she'll get down and 2 minutes later she's all wet or she stays dry forever. We put her down for nap or for bedtime and 5 minutes later she's all poopy. Today, she started screaming for me no sooner had I gotten downstairs. I went upstairs and she had poop all over her hands, up her back, it was oozing out of her diaper...it was everywhere in her clothes. I wound up having to put her in the tub. I will never understand how a little girl poops SO much when there are days that she barely eats anything. It takes her forever to eat. Yesterday it took her 2 1/2 hours almost to eat a sandwich. UGH! I know she's probably developmentally not ready if we're having this much of a struggle with potty training so I only try her for a couple of days a month, but it would be SO much easier if she'd just learn to go on the potty.