Hm, you look pretty good, just two comments.
1. You really start with good knee bend but its not there at the line. If you keep the knee bend at the line your in a better position for leverage and a cleaner release.
2. Your timing is late (IMO from not starting hte ball on your first step in a 4 step approach). This could be the cause of #1 but if you are believing that the timing is a problem your way to fix it is pretty easy.
Overall you had a nice solid shot, i'd work on 1 and 2 if I were you but you looked good, I wish i was to that point.
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Just another aspiring junior bowler who hasn't hit full stride yet.