I am an active duty Airman who applied for the Class of 2024. I have to agree with the previous three posts. While there are advantages to applying as an enlisted Airman, there are also some major downsides. I understand you are specifically asking about enlisting in the Guard component, but I will be answering as an active duty Airman since that is where I am most knowledgeable.
One advantage is that your Squadron Commander is your nominating source. There are less politics involved in the process of attaining the nomination. Another advantage is the extra perspective of consideration. For example, USAFA Selections will be looking at not just your basic requirements, but also your active duty performance. If you are an exemplary Airman, it will be taken into consideration.
One of the disadvantages is that for your first six months to a year (or more), you will be focused on training and learning your job. As an Airman, your primary mission is to learn your job and execute the mission to the best of your ability. Any academic or professional/personal development to go along with that, will come second. Another disadvantage is that you are completely dependent on your leadership. If your leadership does not support you in applying, then your chances of even being able to apply are slim. Now, most leadership will be supportive of your goals, so long as you excel at your primary mission. A third disadvantage is that you will have the possibility of deploying during the time you are working on your application. For some, they are able to finish the application despite being deployed. Others are too busy completing their missions to work on the application.
Enlisting in any branch of the military is not a decision to take lightly. From my personal experience, I would recommend attending ROTC and continuing your academic development. ROTC will give you more overall freedom as well. I would advise against enlisting for the sole purpose of applying to the Academy. If you have any further questions about the enlisted side and the application process, let me know. Good luck with everything!