Yes. The Met is entirely wheelchair accessible. However, if you cannot climb the stairs of the central entrance to reach the meeting point, there is a ground-level entrance one block south, near the intersection of 81st street and 5th avenue. Tell the desk you need to use the elevator to meet a group in the main lobby (at the Pharaoh statue), which will secure your entrance ticket. They will provide you with a temporary pass and help direct you upstairs.