Till what time visitors are allowed to enter the badaling greatwall?

Hi i was wondering what is the time that visitors are allowed to enter the badaling greatwall. I know its open till 6:30 but if I reach there at around 5 or 5:30 can i still buy the ticket and enter inside for a quick look.

My flight lands on 2 pm in the afternoon in Beijing International airport and I am thinking of immidiately going to badaling greatwall. So i think i should reach there by 5 latest.

Hoping to hear from you soon.