There is a batch code at the bottom of the watch which you can go to this website to find the year, https://serial-number-decoder.co.uk/casio/casio.htm, the response is pretty ambiguous though...for mine this is what I had:
21 October 2010 or 2020
There is also this chart if you don't want to go to another rando website: https://www.watchuseek.com/attachments/ ... .12781831/
That's quite a huge difference if you ask me