It would be hard to have two blogs so keep up the same one but add a library component and ideas from your first grade team and maybe guest bloggers. I named my blog in a Primary sense in case I changed grades but that wouldn't help you in the library if you had done that! Good luck!
Good luck with your new job! I hope you continue with your old blog of first grade. I do however understand that keeping up with one blog is hard enough. Two would be impossible for me.