If your mom insurance does not cover for braces you may want to look into a dental discount plan. They will normally save you about 20% off the cost of braces. Metal braces are normally the less expensive ones to get however keep in mind that still going to run around 3000-4000 depending on why you need them and for how long. Some dental discount plans start the next business day so you can have braces as soon as you can afford them. Since you are not to far from working age maybe since you want the braces you can help your mom with the cost of them which might make her be able to get them for you. Talk to her about that and see if it would work for you.
I listed a link below for the dental discount plans if you want to check them out.