This is definitely something to bring up in your lesson as from here on out in jumping you will experience this problem. There can be several reasons for her rushing. Your mount may be unbalanced at the canter, nervous about jumping for a variety of reasons, you could be goosing her, or sharing your nerves with her. As your trainer knows this horse best, he/she is the best to solve this issue.
If your horse says no, you either asked the wrong question or asked the question wrong
And God took a handful of southerly wind, blew His breath over it and created the horse