A full description of the selection criteria is available in
Section 6 of the Admin Manual.
There are no requirements regarding the nominee's plans for future education. In fact, it doesn't even explicitly require that the nominee be planning to attend college*.
It is very unfortunate that your mentors either mistakenly thought this was a requirement. It is also possible that your team made the decision to make it a team requirement for the nomination, as teams are free to nominate any student in either 10th or 11th grade base on whatever requirements the team sees fit.
The best thing you can do at this point is discuss the issue with your mentors so that they are aware of the proper criteria in future years.
* Though the requirements do use "years away from entering college or university" as a substitute for "10th or 11th grade" where those terms are not appropriate, I don't think this is an explicit requirement that the nominee plan to attend college (or university).