Is it normal that i don't eat junk food that much anymore?

I've always ate a good amount of healthy foods for my main meals(breakfast,lunch, & dinner), as I child I wouldn't make a fuss or get defensive when my parents put spinach on my plate. I just ate it like no big deal. But whenever I wanted something quick, like a snack, I used to eat really whatever I could get my hands on. These things included; ice cream, chips, cookies, cake, cheese doodles, Reese's, snickers bars, milky ways, popcorn, etc. And yet, I've always stayed really skinny.

Well, I still am really skinny, but now whenevever I want a quick snack, I'm always searching for something like carrots, celery, yogurt, etc. Stuff that I normally wouldn't find disgusting, but I still wouldn't make it my first choice. Tonight I got home from work, and I went straight to my fridge to look for carrots. Normally, I'd bring home a piece of cake or cookies from work. We had nachos with cheese at work today, and I chose a salad over the nachos!!!! Any other time I would be all over that! So I'm thinking, whats going on?? Why am I becoming this food freak all of a sudden? If anything, I'm probably doing better for myself..., I guess.