Age & Gender / New Beardie

So i got a new bearded dragon on 5-18-19. When i purchase the beardie the owner sold me a light (claimed to be UVB and Basking together) with a 10 gallon tank and at this point i and very little knowledge to bearded dragons. So i went home, started building her a larger cage and doing research. I noticed she was not eating as much as the website says she or he should so this got me worried considering how many issues could come into play. So i made a vet appointment, now i live in a very small town so we have no EXPERTS but she said that she had a couple customers with beardies. The vet said that she seems to look healthy and weighs in a 91 grams,(couldnt tell me age) sent me home with a sheet of stuff to do and to not do (which i already researched). So essentially got no answers, i actually i taught her some things. I have listed below my experiences so far and am really looking for answers.. Please help! I originally posted a long message and decided to break it into categories because I think my chances for receiving answers will be much greater. (See my first post if you would like to read it all!

Age:
The owner told me she did not know how old and couldnt find out so i semi measure the beardie and she seems to be 10-12 inches. ( i didnt flatten her head) So i dont know exactly how old... I found this chart but i dont quiet understand it due to having multiple of the same number in the month spot.

Length (Inches)Age (Months)
3-4 in.0-1 months
5-9 in.2 months
8-11 in.3 months
9-12 in.4 months
11-16 in.5 months
11-18 in.6 months
13-20 in.8 months
16-22 in.12 months

Gender:
The Owner could not give me details on this, so on research i think its a girl. but then again dont know the age so cant identify if i am accurate.

They grow at different rates so it's really hard to say with a lot of accuracy what her age is. At that size she isn't a fully grown adult yet but is probably at least a few months old. I'd estimate maybe around 4-6 months or so, but that's just a rough guess.

This is what you want to look for to help determine gender https://www.beardeddragon.org/forums/viewtopic.php?f=1&t=204533

Great thank you!

yea i have come to terms that not knowing her age is just something that i will have to forget.. and feed manage her food by the observation.