Sometimes, time plays a big role for someone to like, to accept and fall for another person. A year, 5 years, or probably even more.
On the other hand, sometimes it doesn't even take that long for some. A few weeks or maybe a few days are enough for them to know that they have those sorts of feeling.
Why? Because when we talk about feelings, nothing is certain. The connection between two people is a matter of chemistry. Whether or not people want to make a move is another story.
However, what about a rejection or a disappointment? How does a heart take it? How long does one take to get over something? How long does it take to heal a broken heart?
If we got backstabbed or turned down by someone whom we really trust or put high hopes on, how do our hearts take that? How long will the past haunt us till we can get back on track again?
Just a thought though. Nothing personal.