I have had students that did not like the kid looks of some young beginners books. Usually, I try avoiding that, or if I believe that the book is really necessary (that does not happen, cause I do not believe so much in books), I'd try expplaining the teenager that the pictures or the kid songs are not so important as long as they develop their practice.
Now, the Thompson level I, I never use because of the fingering virtually on every single note, which discourages the best efforts to teach music reading. The students always look at the fingers and play in "position", which is very destructive for learning music properly. I use the Thompson from level II and on only.
For a 11 years old kid, depending on the level of understanding and dedication of the person, you could just use none of these method books, teach theory yourself and give little pieces of music that you would find here and there. If the student can't take that or that you don't have time for that (method books are always more comfortable and easy to use), you can use Michael Aaron method level I (not to kidish) or adult learning if the student is smart and quick to grasp ideas.
All the Bastien, F&F, Alfred... are very for kids, so... it's for you to see.