Well, just to say:
Maja and Maria are forms of the same name
Jan, Jaen and Johan are forms of the name Johannes.
Name forms are used very interchangeably in these old records - they certainly did not have the modern ideas of standardization.
Also, when household records give ages instead of birth years, these are a lot less reliable; I suppose the same goes if the age of a mother is given in the birth record of a child. Actually, one comes to expect all sorts of date errors in the household records - even though they are reliable most of the time. One does need to tread carefully with all the name similarities in patronymic Sweden. And it did happen that a widower married a woman with the same name as his first wife...
But, in this case (without looking at the sources) I do believe there is only one person. Please do not make a duplicate just because you are not sure: it is more WikiTree-economic to stick with one profile and make note of your doubts in this profile; then follow her carefully from beginning to end - and IF it should turn out to be two different persons, THEN you divide them up.