OP I also think it is interesting especially since the two languages are so dissimilar. If you make it to AP level for both it is impressive.
I actually regret that S has to “waste” time at college starting French, which was not offered in his HS (he did Spanish). Now he has to make up for lost time while he could be taking Multi-whatever Math or, say, a seminar on Rembrandt, instead of basic vocab. I feel like it is better to get the introductory stuff over and done with, the sooner the better.
Just be sure that you do not neglect your other core subjects. It WOULD be a detriment if you choose to skip math or science in favor of a second language (am assuming your school makes you take English and social studies).