My wife was first chair cello at her high school. For Christmas I would like to get her another cello.?

She needs something to connect to her past. The big issue I have, since I know nothing about cellos,is do I get her a full size cello, or do I get her a 3/4 size that seems to be what high school kids use? I just want to make her happy, and since her birthday is January 1st, she usually gets screwed every year! [B-day and Christmas gets rolled into one!] Thank you to all that can help.