Congrats on getting training and buying lots of good gear, even if it did require a little painful wake up call. After watching a girl snap her ankle like a twig at soccer I bought good motorcycle boots the next day. As you found out, it doesn’t take much for things to break down there.
I think 20,000 miles is a good target before moving up. I have 24k myself now and though I am far from being an expert I know my learning curve has tapered off. It’s been a while since I scared myself which is a good sign. I would also strongly recommend continued training if it’s available to you. I know the advanced class I took this June moved my ability forward by a huge amount and I can’t wait to take the next class.
And lastly, grab a copy of Proficient Motorcycling. That is a fantastic way to learn of (and therefore avoid) all the dangers lurking out there. Certainly kept me safe on more than one occasion.