I am disabled and can't sit on the ground,I have a little taller than the short chairs and have grass seating,can I bring it if I sit farther back?

I recently went to a concert with a friend who uses a wheelchair. We had tickets for the lawn, but we learned (from a kind woman in the parking lot) prior to the show that we could be seated in the ADA section which was much closer to the action compared to the lawn. We got in the ADA line, waited for the gates to open, and then went to the ADA customer service desk - very close to the entrance. They looked at our general admission tickets, gave us ADA wrist bands, and put us on a shuttle down the hill. Folding chairs were provided for those who needed them. This area was not just reserved for wheelchairs, it was a mix of folks with mobility issues. Those of us with the ADA wristbands were allowed to use a restroom on that level instead of climbing up the hill. At the end of a wonderful concert, the shuttle took us (and the other folks) back up the hill. Expect to wait a bit, but overall it was worth it.

I'm pretty sure you could bring it, however the lawn is pretty steep, so it may be difficult to walk around and carry chairs. If you do move forward I'd recommend getting in early since it will be easier when the lawn is less crowded

Yes, just know it's on a hillside (the seating)