我想問下關於天行電腦培訓中心

I think the certificate of the computer center is no use because you are not talking about very difficult computer programming or repairing. 行電腦培訓中心 is only ok--it's the same as borrowing a book from the library and learn it by6 yourself. Many form 4-5 classmates of mine learned by themselves as their familyis not rich and they want to save $. Some even learn by finding the steps on the internet and not using books and learn it very well.
But if you are not talking about learning, you just want to have a few classmates learning with you and a teacher to ask the questions, it's okay there.