My worries about having a mentor is that you have to do things "their way", like all the meanings of the cards become what theirs are. I would really have liked a teacher / mentor who let's you find your own method because my beginner learning was ultimately finding my own place and method in the tarot world. How should I use them? what do I think of this card or this card? It was experimenting and listening to many different ideas.
Some people have posted on AT that they went to classes or had a mentor in the past and you just study one book or follow their method! But you have to follow their method and ideas! My learning method had so many different inputs and ideas, I am so thankful that I found AT in the first year of really learning. So many inputs!
Obviously there is some amazing people with knowledge and unique ideas and mentoring with them could give you such learning. Those people often do talks at tarot events or sessions with web conferencing as well. But I worry for beginners if it really is as helpful as we think it is!
Well, even if we classify Tarot as an art, art schools do exist so there is something to be said about being taught the theoretical basics. When I was teaching I took the decidedly traditional view of teaching the Golden Dawn system which is the underpinning of all modern Tarot decks but has at the same time much room for personal touches and style.
But then, every art form has a theoretical basis which is then developed. There are very few musicians, for example, who get anywhere by jamming in their garages. Some do, most need a basic education.
Not all teachers fit all students. My aim when teaching was not only to teach how to read, but also why each card means what it does and its connections to the others, a fully rounded Tarot education. What they did with it afterwards was their business. Some people want only to learn how to read, quickly, and those people I didn't need to turn away as it was obvious from the start that we would be bad match.