Trick or treating with a disability

Every year I take my sister trick or treating, she’s 19 but she has a mental disability where she acts and thinks like a 6 year old and it affects her badly in other ways as well, I’m quite a mature person and every year since I was about 11, (I’ve just turned 16 now)I’ve taken her trick or treating bc she always tells me how excited she gets and without even taking into consideration about people’s life’s or situations they refuse candy when we go to the door or businesses sometimes or say your too old or it’s just for little kids, and that annoys my sister bc she doesn’t understand and she gets really upset bc she sees them give other people candy and we dress up really good, like i spent $100 on costumes for the two of us so they were pretty good, so if your reading this and you ever refuse an older kids candy, just think before you do it, I know it’s just candy but it’s something my sister looks forward to every year and it upsets her when people are rude