ZK, nice of you to post your video.
You really need to take a course that gets into appropriate racing lines, managing weight transfer, etc. From what I see in your video, you could probably gain most of that 3-second deficit in a couple of outings, but you'll have to focus and concentrate a lot to totally close the gap. Still, it looks like you're having fun and that the whole point. Keep at it and try to get some instruction from successful drivers.