I'm really interested in hearing what people think about this! Obviously the time span will be different for everyone, so I'm asking about personal opinions here. I've looked it up and all, but I think in this case it's better to ask actual people rather than some science-y chemicals. And I've never been in love myself, so I don't know at all. Thanks! (PS, if anybody is wondering why I'm asking this, it's nothing weird. I'm writing a thing and I'm wondering if my characters are falling in love too quickly. And I'm also just curious.)
Depends on the person, and also how you define love. Many people can fall in love instantly, others might take months or years. Also, your characters could just be infatuated quickly which is normal. It's not really loving a person for who they are, but a heated passion.
What my mother always tells me is that if the relationship lasts longer than at least 6 months and you still love them then you know it's real and not "puppy love"