Every character can learn anything he wants, no class restrictions apply. You have different ship and weapon types and you can train skills for all of those if you want, But: Maxing them all would take years, if you also consider non-combat skills it would take many years. The thing is you dont have to do that.
Trying ships or playstyles out, deciding what you like and focusing your favorite doesnt take nearly as long (depending on ship/weapons it's days to fly it, weeks to fly it well, and months to master it). Once you have the skills for your ship type of choice you are just as capable in it as a 5+ year veteran. The older players advantage is in having more choice in what to fly because he mastered more ships and/or other gameplay aspects (economy, exploration). Again you can be proficient enough in each gameplay aspect by dedicating a couple of weeks, master it in a couple of months.
Skill training is passive and mostly a function of time, though some ingame assets can speed it up a bit. So you arent gimped in between while learning something new, you can fly the ship you are proficient with until you considering the new skills sufficient for the next one you want to try out. Also, its not simply a bigger is better situation with ships, it depends on what you want to do. I had 2 characters in EVE that attained a sizable amount of skill points (15 mill and 35mill iirc, might be off) and neither of them could even fly a battleship because I didnt care for it. While most players focus on combat you could dedicate all your training to "crafting" or trading if you want. There are of course specific ships for that too.
Mudflation is fairly limited as far as character power is concerned. Sure there are expansions and new content or balancing changes the status quo, but you never come back after 2 years and your character become worthless because he's 20 levels and 2 expansions behind and could replace all his stuff in the AH. Generally you can come back, read up on the changes and refit your ship a bit to match then go right back to doing what you did before if you want. EVE's skill system is well suited for a long term game.