You sound a little skeptical – “Am trying gardening again.” The Gardening/Landscaping section on here has some great information, and they keep adding more all the time.
I see you plan on doing a lot of heirlooms – check with your local library to see if they have a seed library & offer free classes – mine does. I wrote a blog about it HERE. I live in what would generally be considered a semi-rural area, so it’s possible there is one in your area.
Good luck with your garden. It’s easier, and more fun, than you think.