Homecoming Help!!!

So homecoming is coming up and there's no doubt my boyfriend is going to ask me to it sometime soon. I've been shopping for heels lately and found my dream pair! However they're 4 inch heels..... I'm 5'7 and my boyfriend is 5'9..... I asked him if it would be okay if I was taller than him, and he said he didn't care but I can't help but feel he did that just to be nice. Should I go for the shoes I love or settle for flats?