Is it permissible to repeat the prayer because of not knowing a particular ruling? When I was praying the ‘Asr prayer I had doubts about how many rakats I had prayed, so I performed sujood as-sahw ...

All perfect praise be to Allah, The Lord of the Worlds. I testify that there is none worthy of worship except Allah, and that Muhammad is His slave and Messenger. Making up for the missed prayer ...