First smile happened today and I lost it

My daughter is 6 weeks old and this morning she smiled at me. Like a real intentional smile, not gas. I literally teared up. My wife was like are you crying and I couldn't even explain it. All the sleepless nights, the stress, the feeling of having no idea what I'm doing, it all just melted away for a second. I know it's probably not a big deal to experienced parents but man, that moment made me feel like maybe I'm actually doing something right here.