Get the class one straight away if you have even the slightest inclination to fly commercially.
As previously stated it reverts to class 2 after a year (if not renewed) so has all the same benefits as a class 2. It gets harder to pass the class 1 initial examination the older you get. The yearly renewals are less strict. You may not think this will apply to you and think: "my eyesight is great, never a problem... no problems with hearing etc...", but from experience these things slowly deteriorate over time.
I passed my class 1 with no major issues, but I think the whole thing would have been a whole lot less stressful if I'd sat the initial as a twenty-something rather than going in as I did as a thirty-something.
Best of luck!