Any crossbow and clamp it in a Bogpod. We used a Excalibur Micro and it worked great. I’m also in PA, at 7 years old you gent your own tags. You can shoot at an earlier age but the youth shooter uses the tag from the adult tag holding hunter. Buck or doe, also turkey and some small game.
Look at the Hobbit Rifle thread. That’s the route I went with my kids. TC Encore frame, ar style adjustable stock. Single shot (so they can only shot you 1 time). Good luck, many options.