You can test your v02 max which is a measure of how well your body takes in and utilizes oxygen. There are a bunch of different ways to calculate it but what we did in my college csep-cpt courses was a 1.5 mile run for time and then there are calculations based on your bodyweight and muscularity. Sorry I do not have the books here with the calculations and havent had a need to use them that much so I dont know them off the top of my head but that would be enough information for a good google search and I would highly recommend trying it so you can assign a "number" to your fitness level now so you can measure against it in the future and see what sorts of things you notice have changed from then when your in the ring or exercise in general. This would tell you objectively what your fitness level is as far as aerobic and anaerobic capacity. Your "conditioning" for fighting though is a different but related beast.