Your sentence is grammatically correct, though it might be more natural to say just 'a town' rather then 'one of the towns'. If you worked on the project after your time at school, you could also say: I worked on a project in a town near the school I had been to.
It does rather sound as if the school you went to was not itself in a town. If it were, it would be better to write '... in a town near the one where I was/had been to scchool'.
Please note the corrections I have made, and try to use capital letters correctly in future posts.
Student or Learner