Thinking of returning my OMD

You do not need to spend $5,000+ on a camera to take photos of young kids.  I shoot indoor high school basketball with Nikon D700, but lighting in gyms is dreadful and the action is very fast.  Yet I get a high percentage of keepers.  I've even shot with a Nikon D40 with decent results.  So practice with what you have first.  Increase ISO - you likely need at least 1/250 shutter speed for young kids (I shoot basketball at 1/500).