Is there an age limit for certain degrees in wicca?

Covens are ultimately autonomous. They are run by the High Priestess, and her word is the law. If she says that a year and a day has passed and you only saw 6 months, or 2 years, then she wins. In her wisdom and beauty, she is using a different measure than you. If she says you are 30 and you have only lived 13, then she wins.

It is your decision to discern this though - not hers

Is she really wise?

Ultimately, that is your decision - with guidance from the Lady and Lord.

Most organised covens won't take anyone under the age of majority (depending on where you live that's anywhere from 18 - 21 depending on the country or state). If they're letting minors in, run far, far away or at least proceed with extreme caution and your bulls--- detectors firing. After that, advancement is at the discretion of the people in charge. You might join a coven that has set lengths of time, or you might join one that administers tests in which case you'll only advance once you've really learned the material.

Legally, it is possible to be to young as degrees are only really relevant in organised traditions and, as I said before, they won't take minors. Furthermore, anyone claiming to hold a degree or the title of master at fifteen is full of it. Maturity is valued over chronological age - nobody is ready as a young adolescent for something quite so deep as advanced religious theory. There is no too old, however. Wicca is largely about learning. We're expected to keep expanding our horizons for the rest of our lives.

There's no set age limit for trad wicca, but some covens and teachers have their own individual limits. I highly doubt if many people actually increase their degree in only a year. It's probably more like 5 years average.

A reputable coven won't even take anyone under 18 (at least-- and some covens have older members and so prefer older members).

Each coven generally has their own pacing for training and progressing through degrees. Some require a year and a day just to be initiated into it, and each degree in turn will take longer and longer to achieve because training becomes more and more intense and long term tasks and goals need to be completed.

Some covens tend to push people right through; They have 22 year old 3rd-degree elders. Generally these are started and run by people with little to no training themselves; they put more value on titles than training.

No, there is no age limit on anything in Wicca. I was an Ordained Wiccan Minister when I was 15. I am a theistic satanist now, but I can help you with any wicca pertaining questions you may have. I was a wiccan for about 5 years.

There's no such thing as too old.

Most covens have minimum ages for initiation. It is usually at least 18, but I've heard of several that wait as long as 28, so that they are dealing with fully mature people with life experience. Past that point, I've never heard of additional ade minimums. The entire point of degree elevations is to acknowledge accomplishment. If you've truly accomplished such things while relatively young, then so be it.

Legally they will not train anyone under 18 years of age, and they prefer 21.