This is a simple fix in fact. But not one you can achieve on your own.
You are not, as a cadet, automatically eligible to take all of the exams on Ultilearn. You need to speak to your Squadron staff, and they have the ability to register you as eligible, at which stage they will appear on your account.
There are two explanations for this having not happened. First, it is because your staff forgot, which is easily remedied.
Second, it is because they do not yet think you are ready to take them. The purpose of this system is to ensure that cadets don’t simply register without undertaking any training, relying on multiple guess to get them through.
Speak to your staff, and they can sort it. Either by registering you, or planning more lessons.