My gecko isn't eating on her own, can someone please help?

I just recently got a 4 month old, female, african fat tail gecko from a repltile convention. I also already have a male leopard gecko. For feeding I put the geckos in a bin with paper towel bedding, and throw a few crickets and let them catch and eat them, so they don't swallow any of the substrate that is in their terrariums. My leopard gecko gets the job done, but my younger fat tail doesn't. She just sits there. She hasn't eaten on her own since I got her, and I'm worried. The only reason she has eaten was because I gently pushed down her bottom jaw and put a cickets in her mouth and she gobbles them up.. I want her to be able to eat on her own.. Should I feed her something else instead of crickets that she can catch? or do you think her previous owner just always hand fed her, so she never got the swing of catching her prey? Please help