I got two barred rock/ rir mixes too.. I picked out 3 that I thought were pullets. I just started second guessing myself on the RIR today. No real reason for that except that I don't have a second one to compare it to. I'm glad you think it's a pullet too though. That makes me feel better.
I haven't personally owned RIR's, but I've seen them enough to know that this one should in fact be a pullet. I hope she (or he if I'm wrong) turns out to be a nice hen! (or rooster if I'm wrong which I hope not!)
Yeah, I had a feeling. The guy I got them from had Rhode Island reds and some accidental barred rock/ Rhode Island Red crosses (barred rock rooster got into the rir pen.) The other two I picked were obviously mixes. This one must have been too. He had her in with the RIRs, but she was obviously different from the others. I liked her colors better. Her eggs will just be for eating anyway. Glad to hear that I picked a pullet!