Well, it depends on your and your horse's skill level.
I would talk to your trainer about this. Repeating low jump is necessary so that when you go higher you're prepared and confident. Low jumps are someimes hader to perfect than bigger ones. If you feel the low jumps are boring and you and your horse perform perfectly consistantly, you're probably ready for higher jumps. (Of course, mistakes are always welcome. haha)
Each trainer has different approaches and techniques. Perhaps he/she doesnt feel you or your horse is ready. So have a chat! Have fun.