A 2 year old will fit in it but it won't be as comfortable for you and them as a toddler sized carrier.
This. I do love it, and I love wearing DS in my front, but it's not easy! He's okay on my back, he tends to pull my hair and be a little obnoxious, so I prefer him on my front. He is a bit tall so I have to kind of look around his head a little bit.