Adding fresh to fermented

Hello!! I’ve recently made kimchi for the first time!!! (woohoooo) But I have one problem.. I think I made too much of the paste and now my cabbage doesn’t seem to ferment.. :-( Pockets of air and liquid can be seen in the paste but it isn’t sour enough.. I wanted to add fresh veggies in but I’ve read that I shouldn’t.. My question is can I add fresh veggies into my current kimchi? And can I add fresh veggies into fermented kimchi? If no, why? Hehe thank you everybody!! EXCITED TO TASTE YUMMY KIMCHI!!