Will braces fix my weak chin? If not, what will? (Photo)

Typical contraction orthodontics will be a disaster both cosmetically and physiologically.  I would suggest Epigenetic orthodontics with a DNA Appliance to improve both cosmetic and physiologc issues.  You may have a problem with excess space.
Your undersized maxilla traps you jaw back and can lead to breathing issues, headaches, migraines and TMJ disorders.  Growing he maxilla with Biomimetic DNA Appliance is ideal especially if combined with oral myofunctional therapy.  You could begin with myofunctional therapy and prepare for more successful and faster long term results.

You have very nice teeth and a mild bite problem.  Braces could improve your bite and smile.  
To change your profile, ie to improve your chin projection, would require jaw surgery, probably in both jaws.  
Getting braces now would not prevent getting surgery later if you still want a profile change.