How do I ensure google will crawl my page soon after an update?

I have recently realized that I made a ton of mistakes on my first 45 wordpress posts. I would like to go back and alter them, so they can hopefully rank better.

I am wondering how long it will take before google notices these changes, or if there is anyway I can request them to recrawl the page.

Any advice would be helpful, I am quite new to this stuff.