If you want to go into the armed forces your options are Army, Navy, Air Force. Remember that the number one thing is service to country. Secondly, your goal should be to get in rather than the kind of nurse you want to be. Your life changes completely when you go in. Your worldview changes. Once you go into a hospital, there are many nurses already working in all areas and waiting to get into specific areas such as PACU, ICU, L&D, etc.
As a new nurse or very junior officer, your assignment will depend on rank first and experience. Many new nurses in the service like you have no experience as a nurse, so that is your competitive advantage. Nevertheless in terms of rank, you are at the lower rank of the totem pole. You will move up quickly but you are not walking in as an Ensign, 2nd Lieutenant, etc. into a place where you will also be required to show your stuff as a military officer. That's not happening on day one and I sincerely hope your recruiter is leveling with you about this.
You will have to go to officer indoctrination training first for a few weeks. Then you will be assigned to a hospital that you hopefully selected. Let's say you go to Washington DC. You may be asked to work in step down telemetry or some other unit until a spot becomes available. This is when you start showing your stuff that you brought in from civilian nursing. "Hey, I was an ICU nurse for x years and I can do this with my eyes closed." You would be ahead of many nurses being considered for the spot. Nurses rotate every 3 or 4 years, so once a nurse leaves, you try to get that spot. How do you know and network? Make friends with the ICU nurses. "Hey I'm rotating out in 9 months" boom!!! Talk to your supervisors.
Your second assignment may be overseas where critical care nurses are needed. See where Army, Navy and Air Force nurses serve overseas and those will be your opportunities. Your background will be critical as you will also have to look out for floor nurses not too familiar in emergency care, etc. and it's the middle of the night. This is when you step up. You will have to be very fluid with your goals. As a senior military nurse you will not be doing staff nursing anymore, you will be advance into administrative clinical roles, etc. Such as being in charge of a unit over many other nurses. As you grow in this environment, you will welcome the challenges.
So please consider "I want to work in the ICU once accepted, it doesn't work that way. You will learn from your new fellow officer trainees once you get with them. Good Luck.