Trust your horse. 🙂 Work with smaller jumps until you have confidence in him (or her). When I first started jumping I was so worried about falling because ive had some bad falls too. But you just have to remember they know what their doing.
Starting small and working your way back up is the best option. Having such a big goal will give you drive to keep going so the worst thing to do is to stop jumping all together. A little tip is to not think about how many centimetres/inches/meters you are jumping and thing about it in subway sandwiches. 70cms sounds a lot bigger and two sandwiches 😂