I think you’re looking into this WAY too much. I don’t think she cares exactly how big you are and was just getting dirty on the phone. I think you may actually ruin her little phone game if you get too literal. And who the hell cares if you never met her yet. Plan on meeting her and ask her how much of your dick you can fit in her mouth. Have fun with the phone sex and don’t take everything so literal. How would the convo go if she didn’t say big and hard? Theres not too many other adjectives when you’re trying to get off with words. She’s not going to say, do you have a penis? Do you touch it? Are you erect? Get where I’m going, just have fun.
If you ask her are you wet? Are you soaking your panties? Do you think she’s thinking on the other end “uh oh I hope he’s not truly asking how much I lubricate because he really hates dry pussies and I hope I get wet enough for him” It’s all talk man.