Leggy and transplant

Bring your lights down closer to her - maximum of 18"... if you're really concerned about her flopping over, you can either put a little stick (toothpick?) next to her and gently - with lots of wiggle room - tie her to it... OR you could add more soil around her so she's further into it... roots will start growing from the stem that's now under the soil. As far as transplanting autos, it's a really bad idea, especially for beginners.. it's a stressful "technique" and autos don't like that - next time, they should be germinated in the pot they're going to spend their whole life in... I'd just plan to grow her out in the 1 gallon myself... the problem is that if you wait until she has a decent root system (couple of weeks), she's going to be ready to go into pre-flower and you don't want to disturb that timing by shocking her with the transplant. Her soil also looks a bit dry but perhaps that's just when you took the photo... You should be watering in a fairly wide circle around her - not watering right up against the stem... this will encourage the roots to expand out as they seek water but will still moisten the soil right around the stem, not keeping it wet... And don't introduce nutes until she's about 2 weeks old... start her off at 1/4 strength to see how she tolerates them. You can increase the dosage the next week if all goes well... by week 3, you should be starting to give her a taste of bloom nutes, too.... Autoflowers are finicky but if you practice the "less is more" attitude with them, you'll do just fine. Good luck!