I got Spirit on Valentine's Day when she was about 6 weeks old, she is now 6 months old and is 18 inches long and very chunky lol. She will eat anything I give her for the most part and I think that is why she is so big. My 2 yr old dragon is fatter than Spirit but the same length as her. Now my male dragon who is like 10 mons old never started eating veggies until he was about 8 months old and is 19 inches long but slender. I have recorded a growth of 4 inches in one month in both Shep and Spirit. So I guess my answer is they can grow fast or they can grow slow but I do think it depends on what they eat and how they are taken care of.
7 human kids, 1 hubby, 4 bearded dragons ages 1,13 mons, 8 mons,15 mons, 1 ball python age 4,3 leopard geckos 1 yr and 3 yrs old and unknown age. Our animals are our family, no animal should go unloved!