In Srivaishnava doctrine, one who has not undergone panchasamskaram is unfit to perform Tiruvaradhanam. Given this, how can one perform Perumal aradhanam without committing any offence until one undergoes panchasamskaram?

One who has not undergone Panchasamskaram, must not perform Tiruvaradhanam and no Perumal aradhanam can be done until panchasamskaram. One can offer (Nivedanam) to Perumal, only when one has performed panchasamskaram because the Tiruvashtakshara mantra is part of the Nivedana mantra; Tiruvashtakshara mantra is imparted during panchasamskaram. It is difficult to perform Perumal Tiruvaradhanam until one has undergone panchasamskaram.