I'm another one who agrees!
You'd be far better off with a larger tank; the water will stay more stable and you have many more choices for stocking. I personally, always recommend beginners to start of with a standard three foot (so, that's a 36x12x15" tank, which is about 20g/100l).
My son has a six gallon (a Fluval Edge), but I would never recommend a tank like that for beginners.
First of all, his has five male Endlers and two ghost shrimp in it and that's fully stocked. We don't mind, as we have loads of other tanks to keep things in, but if that was your only tank, it might get a bit frustrating!
Second, the water parameters can shift very quickly. If you're experienced with testing, watching your fish's behaviours and doing large or multiple water changes, it's ok, but to learn on a tank that small could be quite be quite difficult. Everything's so balanced on a knife edge that you don't have a lot of room for error, which you would with a larger volume of water.