I don't think it's weird. I knew I was going to be an industrial archaeologist from about age 12. I am not an industrial archaeologist, because it turns out you have to pay rent and bills, but I still go to quite a lot of industrial museums.
I was a junior member of my local museum for quite a few years, and if that's an option for you, it's a way to see behind the scenes. We also went to quite a few museums on family holidays (St Fahan's by Cardiff was and is a favourite.)
Does she know what area of history she's interested in? I was mad on the Tudors around age 7, though A-level and degree and essays on all the bloody Thomases pretty much cured me of that. And around age 9 or 10, I learned about the 1842 Mines Act, and children working down the mines and it fascinated me, and I have been to a lot of mining museums since then... and mills, and...
I do think most people should know more history. I now work in IT (and have worked with other history graduates,) and for some reason Ada Lovelace came up, and my colleagues didn't know who she was. (I failed to hide my surprise at this, which was noticed.)
But - she's clearly interested. There are lots of possible jobs. Some of them are not paid well at all, and that is something to consider when considering exactly which direction to go in - but a consideration much further down the line, post school, certainly. And there are those like Lucy Worsley who do well. They may be few and far between, but there will be some who make it.