While you can only file in a trademark class if you have a bona fide intent-to-use your name in that class, or already are using it, you have some choice regarding how to describe your goods. 

Generally, a broader description is better than a narrower one. For example “baked goods’ would give you more latitude to grow than, say,  “cupcakes.” Or, “banking and financial services” would give you broader protection and more latitude than, say, “debit card for students.” 

However sometimes you may need to describe what you are claiming very narrowly in order to engineer around someone else’s already existing trademark. If this is the case you may want to think again about your name choice, as your name should not, ideally, constrict your ability to grow but rather, facilitate it.