Unfortunately the answer is YES :( Our son had to graduate to his "big boy" car seat at 6 months because he reached the weight limit for his Maxi-Cosi Micro. A month and a half later he's now at about 24 pounds and still rear facing in the Maxi-Cosi Priori.
CA law is ONE YEAR and AT LEAST TWENTY pounds to FF so if you're comfortable with her weight I would recommend facing her forward. It's been almost two months and there are still times when our son cries even during short car rides. As you probably know, the way that it reclines is a little awkward and uncomfortable for them. It's kind of a halfway recline - just between fully reclined and fully sitting up.
We're counting down the days for his first birthday this September. (And I recently sold my Yukon and bought the new Sienna just for his comfort back there!) LOL
Hopefully she'll be comfy, good luck!