if i were you i wouldn't go as extreme as reining or cutting. i would start off small.
i ride BOTH english and western. huntseat performance/equitation and saddleseat equitation/performance.
its really a lot of fun to do both, but i pick one that i like more [i like western more] for when i feel like riding on a trail or when i feel like just playing around with my horse.
although, its a lot of money to do both, the costs of clothes and tack are a LOT!
You can tell a gelding, you can ask a mare, but you must discuss it with a stallion.