Hi Olivia ! If your tending to lean forward the chances are your riding from your knees and not your calves. Try and tenner to put all your weight in your heels ! Especially when jumping
When I was having the same issue my trainer said for me to lengthen my stirrups a bit more and I also came in more of a ‘defensive’ position coming towards the jump although it wasent defensive it was still more sat back than what I would Normally and staying in a lighter position as said in a previous comment!
Hope this helps
Try to stay light and allow the horse to jump up to you rather than doing such a big movement during two point