The records I have found spell it Donovan, and that she was born in Ireland. But don't restrict yourself to that one spelling. Some records may have one spelling in the original documents, but the transcriber may spell it how they see it, so be aware that it won't always be Donovan.
The same with Jane/ Jenny / Jeny -- that could be Janet, Jeanette, Jeanie, Jeannie, Jennie, or who knows how many other variations. The census records should give you an approximate year of birth, but, again, don't restrict yourself to that as exact. I have seen some people (males and females) who age very oddly in the10 years between one census and the next. Some get younger, some get older, some see-saw back and forth between older and younger. I usually search at least 5 or 6 years either side of a birth year from a census, and have gone as much as 15 years.