It will feel like some one is pushing on your teeth. The brackets stick out a bit from your teeth making it feel like you have a full mouth of metal, big lips and your bracket may rub against your lips feeling again like a metal file.
While some breeds may be more suitable than others for a beginner rider, there are always exceptions to the rule. Quarter Horses often make great beginner horses because of their even temperament, but some can be quite hot or energetic for a beginner.
Hay is the next-best choice. Finding good horse hay can be tricky. It also helps to have hay tested, so that any shortfalls in vitamins and minerals can be compensated for with supplements. For some horses, rich hay can be a problem in the same way rich pasture grass can be.