Don't worry about the fences. Fillers, gates, walls ect all rider scarers. Yes some ponies may find it difficult to focas on the fence due to the colours of whatever but just cause theres a filler, ride it no differently.
I walk the course twice, first time I work out where the heck the jumps are lol and 2nd time I walk the exact course I intend to jump, then I can be sure I'm giving silly mare the best line to jump on and so on
Um have fun! Just enjoy it lol And don't be put off by wizzy kids with big bits and spurs!