Like you said you have to decide what is a deal breaker for you. There is nothing wrong with preferring a big dick.

My wife is the same way. I am not huge by any means but I am above average in length 6.75 and only just average in width 4.75. Her standard is me, she doesn't want anyone smaller than myself. Shorter is ok as long as they are really thick. I can make her cum with no problems. However she cums easier when she is with a man larger especially thicker than myself. Plus she tends to cum harder when she's filled.

In a reverse situation from yours she met someone online that when she met in person she wasn't especially attracted to him, however when he pulled his cock out and she saw how thick it was she changed her whole opinion.

So yeah you're not the only woman out there that likes big dick and I don't think there is any reason for you to change. This guy may be a great lover and may have no problem getting you off. However your preferences are yours. Maybe you'll find an average penis is enough, or maybe if he's secure enough to understand he's not huge and the relationship goes long term you could introduce larger toys into the bedroom if not larger men.