Loads of newbies crash because they underestimate the ability of the bike. Just be glad your first spill was relatively minor, you'll still learn from it.
The closest I've ever come to crashing was also turning at a junction, one that I knew well. A sunny day with trees casting dark shadows over the road on the left which I was about to take.
Brake fine, turn in fine. The turn was more than 90 degrees, say 140, opening out from the initial tightest part. So I hug the inside for a while, wind on the throttle gently and as the road straightens I let the bike move from the inside back out towards the outside, and into the shadows, where there must have been a layer of dirt and gravel between the cars wheel tracks. Both tyres slip sideways across the dirt and the bike yaws to the left, off the dirt, grips, hops and skips, out the seat, wiggle, onto wrong side of road, "oh my that was blooming close" or something like that. Lucky. Learnt I can't ever afford to rely on things being the way I expect them to be.