Hi
Well she has learned that if she "holds back" she doesn't have to go in. The reason she doesn't want to go in is because she probably doesn't want to. Perhaps she prefers to be with you.
You have to teach her that going into the cage does not always mean that you are going to leave her or that all the fun stops.
Leave the cage open during the day with fun things in it. You can even feed her in there and then randomly shut her in when you are there.
Perhaps by now you don't have to shut her in so try leaving her for a few minutes at a time and then when you walk back in just go about your daily business as if walking in and out of the door was the most natural and boring thing ever.
On occasion shut her in at night slightly earlier and then come back in switch all the lights on and let her back out again.
The more you try and force her into it the worse she will become and will learn very quickly that you leaving means everyone gets upset and it will become a huge problem for her.
Hope this helps
Rosie Barclay