Some groups won't take players under 18. Some will. Some won't care. There are a lot of groups here, playing all the half dozen editions of D&D, some of which are similar to each other, some not similar. In addition, there are many games other than D&D that exist, that cover the genres of science fiction, Horror, Action, Science Fantasy, fantasy, time travel, war, espionage, and romance. Generally, you won't be able to create a character until you find a group, because a majority of DMs have specific requirements for characters. Many times you'll be filling an empty slot for a character whose player has had to depart the group for short or long term. You could of course pick an edition of D&D, get the rules, read them or at least the character generation part and get something set up for one specific edition, and then if and when you find a group, suggest playing that one. Some groups allow for almost any character to join. Some will allow for "We Need a fighter-type for a month" (only) I started when I was 11. I basically found a game I liked, called "Traveller" and taught myself to run it, and started running games for friends my age. That was decades ago. Welcome to the community.