I hope this isn't too hard to read.
Here's a strip I did about James and Lily getting engaged... I imagine them getting engaged pretty close toward the end of school, but I can't imagine their parents being totally on board with it, especially since James' parents were kinda old and may have had traditional values and whatnot.
Of course, Pottermore could prove this all wrong but... maybe not.
And Sirius of course would hate this also... I believe JKR did confirm this somewhere but I don't have a quote.
And of course Mr. Severus Snape would disapprove but maybe that's for another comic...
edit- about sirius, he's just jealous that james will be spending more time with lily than him. he's worried the marauders are over~