I've learnt that some carriers are harder than others to get a cat in and out of...
The archetypal plastic front opener can be a right nightmare mainly because the front opening is so small and the carrier is quite dark inside.
By far the best are either the top opening wire ones you see a lot of at shows (open lid, drop cat in, close lid quickly, put latch pin in). They are more expensive but they do last. The other easy type to get a cat in is the clamshell Avior - that's one of the features that attracted me to it in the first place.
I think of your cat doesn't like her carrier, then maybe it might well be of benefit to get a different kind that is more appealing to her.