You ARE husband and wife, yes? Then, what's yours is hers, what's hers is yours. What right do you have to tell her that she can't take something that belongs to her?
If you don't want her to try backing in, setting up, etc., then you should go so YOU can do it.
Sorry, this just hit me wrong and if my DH (we have been married 40 years) told me I COULDN'T take something or do something, he would be finding out just where he could go!
Yes, I agree that it would be better if she had experience in driving it, backing it, etc., but YOU started out with little to no experience, too.
Give her your reasons for not wanting her to take the truck/trailer combo by herself and then make YOUR decision as to what you are going to do.
