I think there is a difference between Mary Magdalen, that she believed and didn’t need to touch to believe. Whereas Thomas, one of the apostles, needed to touch to believe. Also, the bible doesn’t say that Thomas actually touched Jesus’ wounds, but Jesus did offer.
I also just heard, and I hope I can get all this right. . . The Jewish sacrifices were not complete until the smoke rose to heaven. So, since Jesus hadn’t ascended Mary couldn’t touch Him. Thomas **could **because he was a priest and priest were allowed to handle the sacrifice. I heard this on ETWN live, the segment with Tim Gray (he does way better explaining it than I do ) just within the last two weeks. You can still hear the show on-line if you’re interested.