Am I getting special treatment because I look young?

I look young. Unnaturally young. I'm 27 and people mistake me for a fresh high-school graduate all the time. At work, my coworker has been spoiling me since I started. She will bring me snacks, drinks, souvenirs from trips, lunch, etc. randomly. She walks with me pretty much everywhere I need to go in the building, and she doesn't let our manager assign me tedious or unreasonable tasks like he does with everyone else. I try to reciprocate, but she always just says not to worry about it or that I should pay it forward and not back.. I feel guilty because I'm the last one that deserves her kindness. I can't imagine why she'd treat me this way unless she thought I was a fresh graduate with no working experience... should I start subtly letting her know that I'm older? I don't want to sound like I don't appreciate what she does for me, but I also don't want her to waste her time on me.
Am I getting special treatment because I look young?
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