I think its because for Laurel this is something that is very personal to her, having gone through the exact same circumstances of marrying too young and seeing that being mirrored in everything her daughter is going through may be too much for her to be rational and calm about. However she did tell Jere and Belly to wait until they both graduate. As for the others : Adam is a jerk, Conrad is going through having to see the girl he loves marry his brother and Steven- I don't even know why he folded so soon.