Warrior Nation is open to all. The guild is pretty young but we're working very hard to make a name for ourselves as a friendly and active guild. Right now we have a team over 4 admin including the founder who are working to make ourselves the best leaders for a guild you'll find.
Seeing as how you're lvl 18 I believe many guilds would frown upon you and not give you a second glance. We're not like that. Just give us a shot and you'll see what we're all about.