My beardie seems to small

[SketchyAlpaca]

I'll start with I have owned reptiles before but never a beardie. And I did not own this one by choice.
I was thrown into this because a neighbor was moving overseas and couldn't (wouldn't) take the dragon with her and was going to put her outside.
I'll start with what I know.
1. Beardie was purchased September 2020 as a hatchling fancy red beardie.
2. Beardie was in a 10 gal fish tank her whole life (she is in a 40 gal now)
3. Beardie was getting 4 medium dubia roaches a day.
4. Beardie never had water in enclosure. (She does now)
5. She is only measuring 8&1/2 inches long as of 12/28/21 (8 inches as of 12/20/21)
Based on the research I have does she is extremely under sized. But I'm at a loss. I have upgraded her enclosure, she has all the water she could want, she gets soaks and snacks. I've increased her food but she won't eat more than 4-6 large crickets or 6-8 medium dubias a day. Am I doing something wrong or does she need more time?
Is she actually undersized for a 15 month old beardie? As I said I've never owned a beardie so I'm at a loss but I am doing my best.

 

[Sadie]

I'll start with I have owned reptiles before but never a beardie. And I did not own this one by choice.
I was thrown into this because a neighbor was moving overseas and couldn't (wouldn't) take the dragon with her and was going to put her outside.
I'll start with what I know.
1. Beardie was purchased September 2020 as a hatchling fancy red beardie.
2. Beardie was in a 10 gal fish tank her whole life (she is in a 40 gal now)
3. Beardie was getting 4 medium dubia roaches a day.
4. Beardie never had water in enclosure. (She does now)
5. She is only measuring 8&1/2 inches long as of 12/28/21 (8 inches as of 12/20/21)
Based on the research I have does she is extremely under sized. But I'm at a loss. I have upgraded her enclosure, she has all the water she could want, she gets soaks and snacks. I've increased her food but she won't eat more than 4-6 large crickets or 6-8 medium dubias a day. Am I doing something wrong or does she need more time?
Is she actually undersized for a 15 month old beardie? As I said I've never owned a beardie so I'm at a loss but I am doing my best.

Dragons will grow at different rates and times but the MOST important thing in the tank is the basking temps and the UVB that determines their growth --- please tell me what you using for lighting I am going to post what NOT to have
NO colored bulbs NO off white bulbs NO yellowish bulbs NO heat mats or rocks NO sand for substrate and NO COILS for a UVB --- temps need to be surface temps taken w/ a digital probe thermometer NO stick ons they are inaccurate --- basking bulbs need to be a BRIGHT WHITE bulb NO daytime bulbs they have a neodymium coating that is bad for the eyes -- -- the water dish does not need to be in the tank unless she is actually drinking from it
dragons get most of their hydration thru their salads --- she should be getting salads every day now and insects 2-3 times per week --- please tell me what your using