She does not buck or bolt according to the previous owners. I don't know 100% because that was the only time I rode her before we bought her
That could be the reason why she was acting that way. Does she buck/misbehave like this regularly?
Brenna Noble - the day I went to try her out the grooms gave her bath before I rode and she wasn't completely dry and ended up bucking and bolting
I'm not surprised that this is your horse's reaction. Personally I try to avoid putting wet tack on my horse or putting on tack while the horse is wet as it can be very irritating to have the friction of the saddle on wet skin and hairs. Maybe try bathing after your rides, or having several towels on hand for drying your horse off after you bathe.