I started with AG as well (did 1 Mr Beer kit which failed) then made my own equipment and have been brewing all grain ever since. As for propane indoors? I use propane indoors in my basement. Have a fire extinguisher and a CO detector and fresh air in and exhaust fans. The big issue is heat, my little brew room gets pretty warm but now that the fresh air in is 28F the warmth feels good. However, I have low pressure burners rated for interior use, have notified my insurance company and own a house in the woods. So with good ventilation and indoor rated equipment (if the maker says it is then cool) you will be fine. Building restrictions need to be checked ...
But I say go for it. Any pale ale would be a good first brew, something that will be easy to mash and boil. Single Infusion, and fast fermentation. Safale US-05 is a good yeast and is easy and fast. Are you going to bottle or keg? If bottling read the Sticky:
https://www.homebrewtalk.com/f35/bottling-tips-homebrewer-94812/
kegging read :
https://www.homebrewtalk.com/f35/sticky-kegging-faqs-43347/
Good Luck and Happy Brewing!!!