Will I lose my top secret clearance if i become an officer?

No. Many Officer slots require a TS or higher. You might be downgraded to a Secret while you’re in college, but the upgrade process is simple and doesn’t take long.

Your clearance will terminate when you leave the military or retire. Any employer who has positions that require government clearances is only interested in whether you have gone through the background checks that enable a clearance. The employer must request granting of a clearance and can judge how long the checks will take based upon what level you once held and the period of time that must be covered to reissue at the level required by the position he is offering.

You would never lose your clearance, the level may be suspended, otherwise a wast of money. If you do not have an active TS when you are commissioned or separate from service, it is all about the timing of your last BI, generally only good for 5 years with a TS.