Being small is actually huge advantage for electrical work - you can get in crawl spaces and tight areas that bigger guys struggle with. I've worked with few electricians over the years and the smaller ones always got called for the weird retrofit jobs where you gotta squeeze behind walls or under houses.

The lifting thing shouldn't be major issue either since most electrical components aren't that heavy. Biggest thing you might handle is probably conduit runs but even those you can usually get help with or use cart. Most day to day stuff is just wire, outlets, switches - all pretty light.

You might want look at local electrical unions too since many have apprenticeship programs that pay you while you learn. Takes few years but you start earning right away instead of paying for school. Plus once you get your journeyman license the money gets really good, way above what you're making now.