I guess the only change I'd make is NOT breaking my ankle apart before I began to write. But, had I not broken my ankle I never would have written a book. So, I guess no - it all happened as it was meant to. I didn't begin writing until I was in my late 30's. Had I started earlier I would have missed out on years of a lot of things. Had I waited, I'd have ended up leaving my career anyway (my son got really sick a few months after I retired as a nurse to write full time) and then our family would be minus considerable income.
I think they only thing I would change was how I responded to critical reviews in my early months. I would have been a lot more receptive to learning from them. I would have not taken offense.
Not being starry-eyed about being a published author. That should be a real danger signal. Approached things a lot more slowly, and checked and re-checked. There's no one out there to help you. You learn as you go, if you want to save money. Joined at least one writer's group and maybe written a different genre, one that supposedly sells, although given the volume of published content these days, that isn't certain.
I think I can relate to your question a little bit, having just went through this myself.
First, write. Then read. Then rewrite what you didn't like or didn't make sense. Then reread. Reread. Give it to someone else to read and critique (you can find critique groups online and they're free). After they have assessed, then you rewrite and reread again. Don't be afraid to send it off to an editor (also can be found online ie. Reedsy etc.) Once you get it back, then revise and polish. Proofread, proofread, proofread. Be a professional.
When you're ready to convert to Ebook or use KDP they make it stupid simple to import your work and do the converting for you automatically...the key is to have your manuscript setup to pretty much exact industry standards or it will mess up some of the lines on digital formats. Don't try to get artsy with fonts, stick to industry standards. You're not reinventing the wheel, you're writing a book that hopefully someone will want to read and you don't want them navigating through sloppy workmanship.
Once you've uploaded all the files you need, then you have to sit down and think through the timing of your book with any online give aways or ads that you are using to promote your book. Timing is pretty important since you will want to run promotions with outside sources as well as amazon so they happen at the same time, make notes of the dates. Promote, promote, promote. If you think people will flock because you put a book up you will be disappointed, so be a realist. Social media is essential if you are trying to reach any kind of specific target group.
Lastly, keep doing what you're doing with asking questions--next time be more specific.
If I had my time again, I would have started publishing with Createspace at the same time as I did with KDP. Stupidly, I thought paper books were on the way out and Kindle was the way forward, and I missed out on about a years' worth of potential income. Now, most of my income comes from Createspace books rather than Kindle versions, and sometimes I don't even bother creating a Kindle version because I know it will only sell about 1/20th of the paperback version.
Publish as an eBook sooner. I did the iUniverse option in 2009, just to see a book in my hand. I did one more book in 2010. I sold 98 books up until spring of 2012. Life got in the way, and I didn't write any more for awhile.
At an airport lounge in 2012, I saw a man with a Kindle, and we started talking. I told him I had a book in the same genre as what he was reading. He said he'd buy it and tried to find it on Amazon, only it wasn't there.
After I got home, I contacted iUniverse to ask them why it wasn't available. They told me I hadn't paid the $90 for conversion. I paid and got the two eBooks into Amazon. I did a free promo, and after the promo was over, I sold 700 books that month. I did some research, ditched iUniverse, and my writing career started.
So to answer your question, I would have self-published on my own in 2009 instead of wasting three years.