My friend, I'll share my honest feedback with you. YES, you've a very bright chance to get ITA before December I would say.
I understand how you must be feeling still waiting at 451 (the same way I was waiting since February at 450), but never ever lose your hopes. It's just a temporary phase in your life and it shall pass soon.
The good part is - your birthday is falling late December, so trust me, your ITA is secure 100% with 451 score. Since now ITAs have been increased by CIC, you'll notice 3,900 ITAs also soon. You'll surely get your golden ticket before December!
I wish you good luck. Just be more patient for couple of months, you're all set then