Am I too early in my career to moonlight?

I'm about 4 months into my first job as a PA and wanted to get some perspective.

I work in a 3 provider ICU (myself, another PA with 15+ years of experience and an attending), but my role is pretty specialized. Most of my day is spent doing procedures (central lines, arterial lines, etc.) and handling alot of the lower acuity requests, like nursing questions or family updates while the attending and senior PA focus on the bulk of the major medical decision-making. It's actually a setup I enjoy. They're happy to have someone keeping things moving, and I get a lot of procedural experience while learning alot about critically ill patients and how to manage them. I am certainly not fully comfortable but can definitely tell I'm becoming more confident with my own clinical decision-making each week, even if I'm not the one driving it most of the time.

Long-term, I don't plan to stay in critical care forever. Once we start having kids, I'd probably transition to a lower-acuity inpatient specialty with a more family-friendly schedule. For now, though, I plan to stay here another 2-3 years and keep learning.

Financially, I'm also trying to knock out almost $200k in student loans (currently on PSLF with plans to ride it out as long as I can). I also love to travel, and I'd like to have the flexibility to keep doing that while also planning for a family. 

There's an ED in the next town over that has a PRN opening (through one of the big CMGs, unfortunately but my primary job is hospital-employed/PSLF eligible. Has benefits/retirement/PTO, all that jazz.) Since I work 7 on/7 off, I could realistically pick up a shift once or twice a month when I want and back off when life gets busy. The listed commitment is 2 shifts per 3 month period.

My hesitation is that I'm only 4 months into practice. Even though the ED would expose me to more bread-and-butter medicine and a broader demographic vs ICU level illness all the time and likely help me grow as a clinician, I wonder if I'm simply too early in my career. Has anyone started a PRN job this early? Did it make you a better PA, or did it just spread you too thin? Would you recommend getting another 6-12 months under my belt first?