Couple things

If you want Cyber and only Cyber. Guard / Reserve is the way to go. Thers no guarantee you will get it going Active.

If you started the process today. It will be a year or more before you would go to Basic and Tech School. Maybe a lot longer

Going Guard / Reserve has its disadvantages. You will get the same training as Active. But only a little experience. As you only do your job a couple weeks a year. Unless you volunteer to work Full Time with your unit

As far as becoming an Officer. Unless you're a Pilot, Nurse or maybe a Chaplain. That will be difficult. Lack of positions and the unit will have plenty of people already in the unit. With years if not a decade of experience working in the unit. And they will be applying for any position that becomes available