Migration Assistant created new/separate user

Hello Everyone! Sorry for the long story here but want to be clear about what I did. I think I made a big mistake and I'm hoping it can be reversed somehow.

I have an old IMAC from 2008, which still runs great by the way. Last year I got married, and my husband bought me a brand new beautiful IMAC. What a guy, right? Anyway, I have been using this new one for a year, and finally decided to move all my old files from the old one. I used Migration Assistant, and it moved everything to the new IMAC, but in doing so created a brand new user. I thought it would just move over my files, but no.

Is there a way to reverse this? I have to sign in as the other user to access my old files. If I can't reverse it, can I get rid of the new user and just wipe all that out and move my files another way? I read on another thread that I could delete the home folder for the new user but I can't find it. Any suggestions would be appreciated. Thanks!