Average length varies a lot by genre and era of time but yeah, 42 minutes is just barely within the range of "normal" for me.
For reference, my incredibly objective scale:
Extremely Long: 80+ minutes
Very Long: 70-80 minutes
Long: 60-70 minutes
Normal / Average: 40-60 minutes
Short: 30-40 minutes
Extremely Short: 25-30 minutes
Grindcore: <25 minutes