from your description it should be an ipad 2. My first suggestion is, don’t update it or it will slow down terribly. Second thing I would do is I would try apps that you use on your main ipad and see if the install (at least and older version) or not at all. Then only you know what you do with your ipads... To give you an idea my oldest ipad is a mini 2 and I left it on ios 10 so that I could play 32bit games that no longer work with more recents IOS versions (or simply keep some 32bit apps I had bought in the past). I also use it as a dedicated music player, with a bluetooth speaker.