@vandrv, don't let the horror stories throw you off: those are full DUAL-DRIVE installations which require the removal of the logic board and everything else. For a standard, in-place direct replacement of the HDD with an SSD, it's a much simpler operation that doesn't require any of that.
Trust me, I was in your exact same shoes. I heard about broken IR sensors, snipped cables, you name it. But I did the research and went through with an SSD replacement for my brand-new 2012 Mac Mini a few weeks ago and couldn't be happier. I'm not a hardcore Mac tech like some of the veteran forum users are here and I found the whole thing to be super-smooth.
I made a very thorough installation guide for people just like you, check it out here:
https://forums.macrumors.com/threads/1529054/
I'm sure you'll be a lot more comfortable after looking at it. Don't go pay a Mac tech to do this for you. It's too simple.