Track riding advice, body position

I've done about 5 track days and I am trying to figure out what I am doing wrong and I need advice. I am trying to get a knee down but I end up grinding my boots first before I can do so. This ends up throwing me off guard.. effecting my line... Is this a problem a problem with my body position or am I on a bike that is too small for me. I am riding a 11' ninja 250r, I know there is no adjustable suspension in terms of dampening but I have the rear shock on the highest setting which has the most clearance. The last bike I had was a gsxr-1000 and an gsxr-600 before that but I never took them on the track. I'm very tall and I mistakenly I thought a 250 would be enough/fun for the track but it's way too slow in the straights, I can catch up to people on the turns tho but I am in need for improvement, bigger bike. I would like to master the corners first but I am afraid my bike may be too small and I am not sure if I am wasting my time on this bike. I also installed some aftermarket rearsets which sit higher but I still have the same problem, I end up grinding my boots before I can get my kneepad down. I am going to install some new handlebars since the once on the bike sit too high and make my body position even worse then it is by default. The attached picture I am not grinding my boots, it's just for reference.https://i.redd.it/u8d5nz3ekj321.jpg via /r/Trackdays https://www.reddit.com/r/Trackdays/comments/a51hwb/track_riding_advice_body_position/?utm_source=ifttt