I'm pretty sure your substrate will be fine, and probably better then blasting grit. Get some cheap/free plants in there to start with, just to help keep nutrients in check. floaters are great, as they can be easily removed as your desired plants fill in.
I'd set the CO2 aside, there is a chance once you get some better experiences and some time in the hobby, you may set up a high tech tank later.
Sometimes it takes a while for plants to get started, and they may go through an adjustment period getting used to the conditions in your tank.
If you can, see if a library in your area has Walstad's book, or can get it through ILL. If you have the time, it's definitely worth reading, and has a lot of good info.
here's the amazon link: