I think you can narrow the field quite a bit. If she was enumerated as aged 30 in the 1841 census (June 1841) then it's a safe bet that she was aged at least 30-34, as adult ages were rounded down to the nearest 5 years. If she was 37 when she died in 3Q 1842, It seems likely that she was actually 35-36 in 1841, indicating a birth year of 1804-1806. So aged 21-23 at the time of her marriage.
It could be that you haven't found the right baptism yet.