if it's healthy it's probably fine. Way to much genetic variance and autos have added variability due to biological timer that controls phase change to flower.
many mutations aren't a problem, while others correlate to more problems. Howis it growing? your eyes are as good as anyone else's. The growth should be similar per week to a photoperiod early on. simply compare to any plant... realize some peopel count time differently and some people are insecure and lie, lol. There is also quite a bit of genetic variety as far as how fast any 1 seed can grow.
Some plants are poppin 11-finger leaves by day 21-24. cotys; 1-finger, 3-finger, 5-finger, 7-9-11 -- Talking 6-7 nodes and a growth tip -- a robust and substantial plant in 3 weeks... you can't expect that but it's a good high water mark to compare.
autos don't take up a alot of space, so fill the space appropriately... having plants of different ages can be mitigated, but it's a pita you can avoid. Varying sizes makes evening out canopies more difficult.