Great question--you have many options--if you are happy with the spacing you can just treat the dark tooth--it can be rebuilt and brightened with either porcelain or composite. With your age I would recommend composite. Be aware that you will need to see a cosmetic dentist with additional training that can accomplish this for you. Ask to see before and after photos so you can be assured that they are experienced with opaquing and layering techniques with composite. Good luck
Crown and orthodontic treatment.
it looks like you would benefit from a crown, but I would recommend some minor orthodontic treatment first. You could use Invisalign to help straighten and improve tooth position before doing your crown for the best results. You could do just the crown, but it may not look proportional without doing the orthodontic treatment unless you're okay with leaving some space between the two front teeth.
Douglas Jopling, DDS Dallas, Texas area
Chipped tooth, What to do?
The material used to fill you tooth when you were a kid was not silicone, but composite resin. It looks really good at the moment but does tend to darken and pigment with time. You may just change it for new composite restoration or if you want a more teeth-like and more permanent fix you might consider porcelain. Observing your picture, I would recommend to fix with composite resin to look better while you get braces to straighten your teeth, and then to the porcelain.