Is 139 IQ average for a thirteen-year-old female?

The average IQ is 100 for all people, regardless of gender or age, so your question should simply be "is 139 IQ average for person?"

To answer your question, no. 139 is very high, in the gifted or near genius range. Only about 1% of people have an IQ that high. However, if you took a test online, it is probably inaccurate. If you really want to know your IQ, you'll have to take one in real life.