Your age will not be a problem in looking for an agent or a publisher. Here’s why:
Querying agents and publishers involves submitting query letters and manuscripts through the mail. There is absolutely no way they are going to know how old you are unless you tell them. So this is seriously not a thing to worry about. Tell them if you want. Don’t if you don’t. Here’s what Jennifer Laughran, a wonderful agent, has to say about teen writers submitting to her (read link for the long version):
“If the book is truly outstanding, it doesn’t matter how old you are or how much experience you have. There is no reason that a minor can’t have an agent, they would just need to have their parents involved if they are under 18. That said, it is really hard to GET outstanding without a certain amount of experience.”
Here’s what another great agent, Kristin Nelson, says about whether to mention your age in a query letter to an agent. And here’s what Steph Bowe, a published teen writer, has to say about the business of getting published when you’re a teen. Now here’s my advice, the long version.