I went to the dentist for a night guard and been told i better get braces bcz my bite is deep. i don't see anything wrong with it. how is that ?

Good advice: Normal overlap between your front upper and lower teeth is generally 2-3 millimeters (or less). Your frequent headaches at age 20 may be due to a misaligned or bad bite, this greatly concerns me. The mouth guard will only help with the symptom but not fix the real problem. See an orthodontist or prosthodontist for a second opinion, but i think your dentist gave you good advice.

Depends: Your dentist is referring to the way your top & bottom teeth come together. They may still look beautiful but if when your teeth touch completely , if you cannot see any ( or very little)of your bottom teeth this is called an overbite. If too deep it can contribute to TMJ and other tooth grinding issues. You can always have a consultation with an orthodontist to discuss issue.

2nd opinion: My advise to you get a second opinion and if it is possible find a neuromuscular dentist to evaluate your tmj.

Degrees: First, the degree of overbite varies. Secondly, when evaluating a patient's need for orthodontic treatment, the overbite is only one aspect to be considered. Third, what a dentist sees is different from what is or is not apparent to a patient. Fourth, people can exist without orthodontic treatment & night guards. It's a choice.See 2-3 dentists that you respect until you understand what is best 4 u.