There's no reason you need to have c02. It's pretty ridiculous to me to have waited that long to use the tank. Just because it's an ADA tank doesn't mean it's a law that you have to have all high tech stuff and a glorious iwagumi setup. Just change your expectations and start your tank right away. If in the future you have the funds, then you can always switch to high tech, but in the mean time you can make a gorgeous low tech setup that some lucky fishes will be happy to live in.
You could also consider going low tech and house shrimps who (at least in my opinion) do great with low techs. Trust me, shrimps will be more interesting than watching your grass grow and pearl if you had a injected c02 setup.
So don't give up, just change your unrealistic expectations of the "perfect tank" that you want to make. Some plants thrive with c02 so just don't get those kinds - focus more on low tech plants and you'll do fine. Stop wasting time with an empty tank and start your tank already!
... also, if it makes you feel better, everyone and their mother is trying a HC tank. Be original and go a different route.