1. You should start to monitor her more closely at about 6 months of age. For now you have nothing to worry about. Just keep feeding her daily and let her eat as much as she wants. You're supplement schedule should be: Calcium phosphorus free every feeding, cal with D3 twice a month and a multivitamin twice a month on alternating days of the D3.
2. A large screen cage is best. Reptibreeze makes good cages along with Dragon Strand. A basking bulb along with a UVB bulb are both required. Baking temps should be about 82-86 degrees with an ambient temp of 70 degrees. Have plenty of live plants in it such as ficus, pothos, umbrella plants, etc. Plenty of horizontal and vertical perches and branches should be in ghere. If she isn't basking, you shouldn't be able to find her very easily. That's when you know you have enough coverage. You should keep a laying bin in it at all time that's an opaque container filled with washed playsand in her enclosure. It should take up just about the whole floor of the enclosure. The bigger the better. Especially being veileds are picky. Have 10 inch deep sand in it. Make sure there's a drainage system on the bottom to allow water to drain out of the cage. There's other threads on here about drainage systems.
3. Once she hits about 6 months of age or sexual maturity, start cutting back on her food to every other day. This helps to reduce the clutch size she lays and is easier on her body. Keeping her temps at 82-86 also helps in this area as well.
She looks to be about 3-4 months IMO. There's plenty of good people on here always willing to help! Good luck!