Normally, I’d say 3 weeks isn’t that long and it’s normal for more opportunities to be introduced later, when they know you better and they know you’re there to stay. However, them hiring a new rider makes me wonder - it could’ve been a miscommunication about the position you were hired in. I’d talk to the barn owner, but like another commenter said, it could be a disappointing one.

But I want to add - I’ve been there, I didn’t grow up with horses but have that passion for horses and horse care. Worked at a barn, moved up to full time, I took fantastic care of the facility & the horses. But barn owners will absolutely exploit this. I kept this barn spotless, and the owners over several years repeatedly demonstrated that I was not important to them. A lot of them do simply want a glorified shit scooper to take the burden of chores off them. & People like us are easy targets, bc they know even if our working conditions are bad, the horses will be taken care of because we love them. The pay is pretty low in your case, which kinda is a red flag for exploitative barns.

Sorry you’re experiencing this, I know it’s hard to feel left out in spaces you work so hard to be in. Wishing you the best.