I would go with the biggest tank you can, but i would think about more then just what you can afford also think about the maintenance of the tank. the bigger the tank the bigger the water change you will need to do the more dosing ect, bigger tanks are also more work, even if they are easier to keep your parameters in check.
And like afdoundguy said 55 are really not that good and take your time, like i am sure you have read before nothing good comes fast in this hobby. And have fun, things can go really wrong fast so don’t let this hobby get the better of you.