no age restriction just remember you will most likely get a high bar table with no seating, only about 20% of the cantina has seating.
The land does die down after 7pm so it is the best time to visit
Don't settle for one of those "bar tables." Worst of both worlds - you're standing, but you don't have easy access to your bartender.
Politely ask for seating at the bar, it's the best place to be. Fastest service and a chance to interact with your bartender(s).