That depends on which kind of speed you mean. She's not really near Quicksilver in speed, at least not that we've seen, but she is significantly faster than normal people, and not only is she faster, but she also has better reflexes and is more agile, making her not only faster, but able to react and perform faster than normal people.
However, when she's flying she's exceedingly fast, able to keep up with jets with little issue. She doesn't appear to be this fast on the ground, but that may be due to her wish to fly instead of run places.
Hope this helps!