First, check out the link I included. There is a nice discussion on love vs. infatuation.
The irony of using this quote is that it is the only time that anyone shows something like love. Shortly after this, Juliet decides to trust Romeo, which shows she feels something beyond the situational excitement of infatuation.
However, you have said that you are trying to connect this monologue to infatuation, so you may want to focus on her references to physical beauty. Juliet refers to Romeo as having "a flowering face" and "sweet flesh." Her positive side of nearly each metaphor is about his looks or his being divine to some degree. Infatuation often focuses on physical attraction and engulfs both parties so much that it seems they worship each other, so the heavenly references and focus on beauty could point to infatuation.
Here are a few arguments that might help you:
1. Juliet's quick dismissal of Romeo after Tybalt's death shows that she was focused on Romeo's external beauty and was not truly in love with him.
2. Juliet focuses on Romeo's physical features rather than expressing any dismay about his actions, so their attraction is more akin to infatuation than love.
3. When Juliet hears that Romeo killed her cousin, Tybalt, she does not defend him; nor does she seem surprised by his actions. Rather, she immediately condemns Romeo and expresses remorse that his beauty is not matched by his heart.
4. Juliet reveals an infatuation with Romeo rather than love when she denounces Romeo rather than defending him, focusing her condemnation on his character not matching his physical beauty, a condemnation that shows how quickly she thinks the worst of her new husband and how little she thought of his character before marrying him.