Humm... This is a very intense decision for you. Not knowing your background, and not knowing your environment, it's hard to offer any other suggestion than to NOT join a gang.
Step out of your emotions and look at the facts. Your considering about joining a gang because:
*You suck at school
*You have no ambition to do your school work
*Your Family (assuming your dad) yells at you when you don't do what he wants
*Your friend want's you to join.
Let me look at each one of those reasons individually.
[you suck at school]
I don't know the Maryland school system, but most schools offer many programs to help students excel acodymically (

sorry, can't spell it). There could a situation where your in the wrong level of courses. Either it's boring for you cuz there's no challenge, the peer group accepts you better when you "suck at school", or the level of courses your taking are too hard.
Either way, there are numerous things you can do to improve.
[you have no ambition to do your school work]
Lack of ambition is often attributed to depression. Also, most kids have lack of ambition when it comes to school work. If the first reason [I suck at school] get's addressed, your ambition to work harder in school will come.
[Your family "dad" yells at you...]
Like I said, I don't know your situation, but being a father myself, I find myself yelling at my son. It comes from the frustrations of loving my son, and wanting him to be the best that "He" can be in what ever he does. Some of it isn't even directly related to him, maybe I was just having a bad day, and he did something that set me off.. I love my son dearly and constantly work on being understanding, but at the same time, he's constantly testing the limits and bounderies.
Just be glad that he at least yells at you. It's much better to be yelled at than just ignored. That means he's acknoleging your existance and that he's noticing you. You might asking for his help, if he's tentive enough to yell at you, he might be willing to offer some suggestions that you could learn, and apply to your life. That's what a Parent/Child relationship is all about.
[Your friend want's you to join]
Why does he want you to join? What does he have to gain by you joining? Is it worth the sacrifice to be in a gang for your friend?
When it comes down to it, after everything comes crashing down, all that's left is you.
There are plenty of work-arounds to help you though this part of your life without having to join a gang. I don't know your religious background as well, but for me, it's nice to know that I will be taken care of no matter what.
I hope I've been able to give you some insight.
