Well, in my opinion you are qualified. The stats on HSing are pretty good - HSed kids score well on standardised tests, go to college and University at the same rate as public schooler, etc....and very few have parents who were teachers! The research is easy to find, so hopefully you can lay this concern to rest pretty quickly. Honestly, what you (may) lack in expertise you will more than make up for with one-on-one attention and hand picking resources that work for her.
As per your DD needing to be with other kids - Dh is right! Your DD does need to interact with people of all ages - but I doubt you live under a rock. Church, classes, swim lessons, neighbourhood kids, camps - these things count. Some people do have difficulty meeting their kids social needs through HSing but some don't - and there is only one way to find out.
Lastly, your DD is definitely old enough to let you know if something is working or not. Let her sit with HSing a bit and if she wants to try it, go for it. If she tries it, and after trying it for a while does not like it, she can always go back.
I wouldn't recommend 1/2 year HSing and half year PSing (and if you do try it - do PS first rather than transition a child into PSing half way through a year). Trying Hs for one year and then re-assessing as a family may work. I do think as children age they should have more say in where she goes to school. I wouldn't want to PS or HS an older child who wasn't happy with where they were learning.