I'm trying to build a regex for a field containing the number of months, of course, this needs to be only numbers 1-12. However, new to regex this is a bit new to me and I just need to check I'm right. It seems to work alright. Although, am I correct in assuming the range here 1-12 allows any number in this range, I only ask as I've only ever seen it done with 0-9 before.
This might do. Two digits or one digit
Edit: If you're worried about numbers like 55 use this:
$ means start and end of string. Use https://regex101.com as a good learning tool.