He can use anyone

I thank him who has given me strength, Christ Jesus our Lord, because he judged me faithful, appointing me to his service, though formerly I was a blasphemer, persecutor, and insolent opponent. But I received mercy because I had acted ignorantly in unbelief, and the grace of our Lord overflowed for me with the faith and love that are in Christ Jesus. (1 Timothy 1:12-14 ESV)

God can use ANYONE rearguardless of their past circumstance.  His grace is enough.