I think that there are basically only two possible answers to “what are my chances at Harvard”. For exceptional students the answer is “It is a reach, it is worth applying but focus on finding good safeties and matches”. For most students the answer is “forget about it”.
You get the first answer. You have done exceptionally well up to now and are a competitive applicant at any university. However, 80% of the applicants to Harvard are also very strong competitive applicants.
Good luck and best wishes. I think that you will do very well regardless of whether you end up at Harvard or at a different university.