What chances do I have to obtain f2 status?

If: 1) your F1 status was continuously valid all this time and remains valid now; 2) your wife's F1 status is valid now; and 3) your family has means to support itself in the U.S. without employment here - then your eligibility for F2 is clear, and there is no apparent reason to doubt its approval. Should you wish to exercise an extreme caution, you can continue your full-time enrollment on F1 until you get a decision on your change of status application (about 2.5 months): if your change of status gets approved, you can drop out from the college; if it gets denied - you just continue in F1. If, however, you did not maintain the minimum required coursework, accepted unauthorized employment, or otherwise failed to maintain your F1 status, or if you cannot show the financial ability to support yourself and your wife in the U.S., then the chances of your change of status application being approved are not 8% - they are exactly 0%, and you should consult an immigration attorney to find out whether you should leave the U.S. to avoid becoming subject to a 3 or 10-year bar to re-entry.