How did you know you loved him?

I've been dating my boyfriend since September 15th and last week he told me he loved me. He started talking about the way i make him feel, how he's becoming a better person because of my positive attitude, and I thought it was super sweet and told him I just didn't feel the same. He respected that.

But like, I don't know what love feels like. Sure, i still get butterflies when we hang out and when think about meeting up with him. I love that we challenge each other intellectually. like, i have a lot of love for him, but I'm not in love with him. I'm comfortable. He makes me so incredibly comfortable and calm.

Like, I like him more than a friend but im morning love with him. am i making sense? this is my first official relationship and dont really know what this whole love thing even means.

p.s. if age matters, I'm 22 and he's 24.

but when did you guys realized you loved your boyfriend? how did you feel? what we're you thinking?