Why could Thomas touch the resurrected Christ but not Mary Magdalene?

So in St John Ch 20 it talks of the resurrected Christ in vs 17 it says "Jesus saith unto her, Touch me not; for I am not yet ascended to my Father: but go to my brethren, and say unto them, I ascend unto my Father, and your Father; and to my God, and your God." (KJV) but then in vs 27 it says "Then saith he to Thomas, Reach hither thy finger, and behold my hands; and reach hither thy hand, and thrust it into my side: and be not faithless, but believing. " (KJV) so why was Thomas allowed to touch Jesus but not Mary Magdalene?