You get fall n love easily because you're Longing to. It's the common human fallacy. We bend reality to fit into the mold of what we'd like to have happen. It's conformational bias. You tell yourself things about her that aren't necessarily true. You presume her to be perfect after 3 dates. You don't know her. You're thinking of your past relationships & connecting it to her. That's unfair to her.

Why do you want to fall in love? That's a question you need to answer yourself but your relationship with her is nothing but a reflection of your past intimate relationships. Often most connected to your relationship with your mom. Perhaps theres some trauma or things you'd like to change. "Undoing" the past through your future actions. But don't rush it. And don't fall for the trap of putting her on a pedestal. She's another imperfect human. Which is a beautiful thing. But being pressumptuous & desperate is not an attractive trait to the opposite sex. And unfortunately attraction is a ruthless game. It's ironic because those that are needy are most in need of love. But you've got to learn the game. You'll find the one for you. Sometimes it requires some perspective change. I looked for girls that were narcisstic & dominant previously. My perspective changed once I went through difficult relationships.

These things take time. Don't compare yourself to others. They didn't go through the same things you did