How do you know when you’re ready to have sex??

So my girlfriend and I are both 19, I’m still a virgin and she’s very experienced. We’ve been dating for awhile now, and she said whenever I’m ready, we’ll have sex. I’ve no clue how to know if I’m ready, but she’s the best, she is not rushing me whatsoever. I have sex dreams about her relatively often, does that mean I’m ready? Or will I just know? I do believe I will lose my virginity to her, I’m very comfortable around her and I honestly love her so much I get emotional when I think about how much I love and need her. Please help, and please no judgment.