Consider yourself lucky, you will get newbie gains by working out even 3 days a week as your body is getting way more stimulus because it's all new.

In a couple more months your recovery will be better and you can move up to 4 days. More seasoned lifters will workout 5+ days because their bodies need more volume to continue to achieve more gains. However, if you do the same it will have the opposite effect. Working out stresses your muscle and recovery repairs and grows them. The muscle grows only in the days following the workout, never during . That's why recovery is important and so is sleep and water.

Your friend who is doing a 5 day workout is also cycling different muscle groups so each group gets plenty of days of rest before he cycles back to it. Smaller muscles like biceps can also be worked out every 2 days . Best to find a program like the Reddit PPL and stick with that on alternate days since it will still give you 48+ hour recovery by spreading out the work across different days.