First ever Data Analyst job offer, but company is (kinda) clueless about the field?

I come from a background in Environmental Engineering, but I developed skills in Data Analysis because of my research field (Meteorology). I learned mainly about Python, with some R and SQL on the side.

Now, I graduated months ago and every application I have sent to do this "shift" into Data Analysis has been met with silence. I applied to this company where they required Python, SQL and data visualization skills and after a couple of days they called me and told me they were interested.

I passed the first couple of filters then during an interview with the HR coordinator (it's for people analytics) he told me they all know a bit of Excel here and there but the company is just about a year old and around 3 months ago they realized their data collection and management is a mess (I'm guessing they have a bunch of Excel files from manual input), so they're bringing it a Data Analyst to tiddy it up and provide insights (So you see, they asked for stuff like Python and R but don't actually know how it works - "code for cool stats and graphs", or something like that).

That's the thing: I have SOME experience with things like SQL, but I don't know EVERYTHING about it, and have never ever created a database from scratch with real scale data. I was told I seem like a good fit, but would be the only Analyst supporting this process, and they are on the process of sending me the job offer.

I am really nervous about accepting, mainly because I would have no real mentorship into developing techincal skills and because I fear I could completely fuck up this company's data and be punished for it.

I'm looking for some desperate advice since this is the only offer I've gotten, what should I do?