I think that the matter of Mu‘adh (rta) is quite different from that of yours. He had offered his obligatory prayer before leading the prayer in his own tribe. Had you offered your ‘Asr prayer and later found the congregation, then you could have done so. Since you had to offer your ‘Asr prayer which is obligatory to offer within the prescribed time, you cannot leave that and offer the missed one which you could now offer anytime. However, it does not mean that you need to repeat the prayer. You used your reason, which unfortunately led you to a wrong conclusion, but none can render your prayer unacceptable. You need only to correct your view and act accordingly in future.