I am studying for the PMP certification and it requires 3 years or 4500 of PM experience. Does being PL and XO count as experience ?

The PMP Study course, is basically a test requirement, it fits very well into basic officer leadership, although the budget stuff is only applicable when you get into the contracting sector of the Army. Private sector uses the budget as the driver for decisions where public sector budget is a limitation rather than the driving force, so much of the EVMS things you'll need to know to pass the test don't really apply to military projects involving in house personnel only.
As a LT in IT I'd focus on a core competency, what is it that you really want to excel at, networking system, satellite, IMS, tackle one of those so you can demonstrate technical expertise and individual capacity for intelligence. Too often technical competency is overlooked in the Army Officer corps. I'd start with the civilian IT certificates. In a few years that technical base will make your future job prospects as a project manager much more achievable. (There are many quality leaders coming from the Army but very few leaders with a strong technical foundation)

good advice

MAJ (Join to see) - Sir,
On the note of Officer core competency and development what have you seen that 01-03s overlook?

They delegate so much to their NCO's that they don't learn the basics of their tradecraft. It's a fine line of perception between micro management, and shirking your responsibilities by pawning off all work to the NCO's. You want to make sure you learn their jobs while not subverting or interfering with their ability to execute the tasks. It's not really something you can learn at the 03 or 04 level, so make sure you pay attention to what your NCO's are teaching. In the engineer world that amounted to OSHA standards, quality construction standards and code, for IT that means knowing exactly how to setup, and run a network, too many officers depend on their nco's and couldn't do it if their life depended on it, while other's stifle their NCO's by not allowing them to do anything without direct officer supervision. A good NCO will help you walk the line, a bad NCO will tell you to stay out of their lane. I was partially successful as a LT, platoon sergeant dependent. Good Luck.
After you leave the military corporate world will expect you to do everything until you reach the senior management levels, if you retire without a LTC+ rank you'll need a solid core base to fall back to rather than depending on your leadership experience.