You are definitely allowed to retake it. I can not tell you if there is a waiting period.
What I can tell you is:
It makes a lot of sense to have some project expierience before you do the advanced exam. The learning paths are great and contain a lot of good information, but in the exam you need to do things on your own in a limited time. But as I don’t know how experienced you are or how your background is, I can not give a suggestion to you.
Also make sure to get some experience of the Mendix Developer platform itself. The exam is not only about functionalities in the modeler but also to make proper use of the platform and best practices. Such as using the user stories in sprintr and feedback items for example.
Good luck if you are going for it!