Tennis is a very well loved sport in many countries. It originated in France in the late 1800's. Unlike some sports tennis is the same in every country.
Tennis is a farely simple game, so it makes it for all ages, it doesn't matter if you are older or younger. Tennis has three things you cannot do. The first is you cannot touch the net or net post. Another one is you can't carry or catch the ball with your racket. And finally the third is you can't hit the ball two times in a row.
Tennis has it's own language compared to most sports. There are games, sets, and matches. You end a game by winning 4 points. You usually end a set by winning 6 games. Matches depend on the age level and compition your in. Most matches end after 2 sets. For big compititons like Grand Slams (US Open, Wimbledon, ect.) males will play 5 sets.