Advice For Wife Anal

My wife proposed to me last night that when we go to Mexico in a couple of months she is going to let me put it in her ass on condition that she gets to do it to me first... I'm not sure how I feel about it. I have let her run my asshole while giving me a blowjob but nothing has ever gone inside me. I'm just wondering what others think of this situation if I should let her or not.

Thanks,

Carl