Stuttering has been shown to be linked somewhat to hormones (i.e., might come back or diminish). I myself remember being somewhat fluent, and it going all to shit at around 12ish. My speech became fluent-ish though at around 18 and now it's extremely mild. I'd wait it out and see. There are a bunch of methods online (if you cannot go to an SLP) about how to "control" it. But I wouldn't stress too much about it :)