There are very few reasons(if any) to build your own engine when you can so easily and cheaply(or even free) access tools like UE or Unity that have years of work put into them. You'd have to have some very specific needs for that to make sense nowdays, really. Unity is great, especially for starting out, I'd definitely…
I have a little bit of experience working on an indie title with a graphic programmer. Pretty much his entire job revolves around making an engine do stuff and on his spare time he built one from scratch. I got on board to make art for the indie title a few years ago and by that point he had been working on it for 3+…