Yeah, the creators have suggested several times that Emma and Snow are roughly the same physical age now. So that would put her around 29.
Wreaks havoc with the timeline, though, because that means that Regina was queen from the time Snow was about 10-12 until she was 28ish. Depending on when Leopold was killed (and Snow looked around 18-20 at best then), there could be a decade between the Huntsman releasing Snow and the curse, but most of what we’ve seen of FTL seems to have happened within the last 2-3 years before the curse. Especially tricky are things like Hansel and Gretel who had to have aged at least a year in FTL (the apple was before the marriage and the marriage before the pregnancy and…math) but don’t look one bit older in SB.
Keeper of Belle's Gold magic, sand dollar, cloaks, purple FTL outfit, spell scroll, library key, copy of Romeo and Juliet, and cry-muffling pillow, Rumple's doll, overcoat, and strength, and The Timeline. My spreadsheet: https://drive.google.com/file/d/0B6r8CySCCWd9R0RUNm4xR3RhMEU/view?usp=sharing