Levels only affect what clan you can join when clans set their joining requirements at levels higher than yours. There's plenty of clans that have no level requirements to join, and you don't even need to stay in the same clan forever. You can leave and join other clans until you find one you like, but I'd recommend researching a bit before joining to simplify that process.
Any time is a great time to join a clan, regardless of what your levels are.
If you want to advertise yourself as someone seeking a clan, post a new thread in the forum section:
Looking for a Clan
In that thread, include a bit of information about yourself as well as what you're looking for in a clan, and you'll get replies from clans who are seeking new members.
OR
Browse the following recruitment sections for a clan that interests you:
Even if you don't know what you're looking for, take some chances and you may meet some good friends and get worthwhile advice on how to progress further into RuneScape.
Good luck! If you have any other questions, let me know.
~ Sicariu
Leader of