You are not ready to carry, despite what the license says. You've only learned how to handle a firearm safely by yourself. Getting proper CCW training, especially understanding the legal side of things should you get into a use of lethal force incident is crucial.
Wait, wut? I respect your advice, I truly do, and I understand the intent, which is admirable, no doubt. However....
Although I am a huge advocate for training, I am a bigger advocate for not getting dead.
Assuming the OP is a reasonable adult of at least average intelligence, that is unlikely to shoot the girl working the drive thru because they ran out of chicken nuggets, let us not forget the first rule of winning a gun fight, which is, "bring a gun."
OP - you should endeavor to seek out quality training. It is incumbent upon you to become familiar with your firearm and it's safe and responsible use, but this does not mean that you should be prepared to sacrifice your life, or the life of those dear to you, until you have been trained to some arbitrary standard set by others, because some hood booger decides that he wants to relieve you of your valuables.
You never want to be laying in a parking lot bleeding out and have you last thought be, "shit, I wish I had not left my gun at home." Or worse, holding someone you love while they take their last breath, knowing you could have prevented it.
Love Machine is right, you should get training and education, and I have no doubt it is important to you and you will seek such training. Until you do, apply these simple guidelines.
1. Don't draw your firearm in public unless you absolutely intend to use it.
2. The only reason to draw your carry gun in public is to prevent probable death of yourself or a loved one. If you ever have to use your gun to protect yourself, even if you are completely justified, the Commonwealth of Massachusetts is very likely to try to ruin your life. Make sure the person you are trying to protect is worthy of what you will probably be facing.
3. If you do have to pull the trigger, you are responsible for that piece of lead until it comes to rest, and you have to consider this. Which is easier said than done when your heart is pounding, adrenaline surging, and tunnel vision has taken hold.
4. Finally, if you do have to use your firearm, never ever ever ever, talk to the police after the fact. No matter what the circumstances are, even if it is obvious that if you didn't act, you were going to die, never ever ever talk to the police. Don't even answer the simplest of questions.
Be polite and just tell the cop, " I want to cooperate, but I am not going to talk at all until I have a lawyer present." Most people say that you should inform the police that you need medical attention and ask them to call an ambulance, which is a good idea for several reasons. It is entirely possible that you may go into shock and many people have difficulty breathing or chest pains. After a shooting, cops are not your friends. Even if they appear to be on your side, totally sympathetic and understanding, they will twist any statement made, take statements out of context, and use those statements as evidence against you.