Ash is right, if your mom simply added you on to her account, it will not effect or establish your credit rating.
However, if you have applied for/plan to apply for a student loan or line of credit in your name, you will already be establishing a credit rating through these, and as long as you make your payments, you will be establishing good credit this way, and do not need a credit card, though it will actually help things in the future - the better the credit rating, the more you'll be pre-approved for when you want to buy a house or get a car loan.
You can ask your new bank if they have a student credit card, but it's unlikely, as many banks don't issue student cards. If your first week at school is anything like mine, there will be people there just shoving clipboards into your hands and trying to force you to sign up for their student credit card. You don't have to be a member of a bank to have their student credit card.
Things that are super important to know if you are going to apply for a student credit card:
1) Don't apply for more than one card: every time you apply for a credit card, it negatively effects your credit rating and your available debt ratio. Only apply for one card. If you are declined for one, you will likely be declined for them all.
2) Take your time - if there's more than one card being pushed out there, ask to take the application for each back to the dorm with you, and read them over. The important thing to look for is the lowest interest rate - for student cards the rates are normally really high, and somewhere around 18-19% is fairly normal. Yeah, the person will aggressively want you to sign up right then and there because they make a bonus for each person they sign up, and they'll have some stupid give away that you'll probably want, so you can ask them how long they'll be there that day, if they'll be back again, etc. No matter what, you can mail the app. in on your own later, and it is highly suspect if they don't want you to take some time to look the application over. Make sure the card has no annual fee, one that gives you airmiles or other points you already collect, and go for a Mastercard or Visa - some of the other cards are good, but these two are universally recognized, and this will be useful to you later on if you chose to travel, make purchases online, etc. The absolute best feature a card can offer (for you, not the credit card company) is the option for automatic payments directly transferred from your bank account to pay off the balance in full. This will force you to spend only what you can afford to pay off in full, and completely avoid interest. Fewer and fewer cards are offering this option, so don't be surprised if this isn't an option on the cards you're offered, but if it is, set up the automatic payments as soon as you get the card.
3) Once you're approved for the card, look at the credit limit they've given you really honestly. Student cards often offer limits that are impossible for you to pay back on your own, without mom or dad's help. If you want to be a respectable kid who never, ever has to go to your parents for help to pay off your card, call up the credit card company and have them lower your limit to the lowest amount possible- normally the lowest limit for Mastercard is $500 (it used to be $200, but I'm pretty sure they've increased it across the board). When you lower your limit, they will not be able to increase your limit again for a specific period of time - for the card I worked for it was six months, but ask them - it useful to know if you suddenly need to book a flight or some other big ticket item. Also ask them if the card's limit automatically increases over time, and if so, ask them to turn off this feature - I'm not sure if the law's the same in the US, but in Canada, creditors are legally required to be able to turn this function off. This won't close the door to future limit increases, but it puts you in better controle of your spending, because you'll have to call in and request the increase if you want it.
4) Never ever ever ever ever use your credit card to get a cash advance. Unlike other purchases that only accumulate interest after a month if you don't pay the balance off in full, cash advances accumulate interest on the balance in full from the moment they're taken out until they're paid off in full. Cash advances and balance transfers are how credit card companies make their money, avoid them like the plague.
I could go on and on about good spending behavior. It's pretty dorky, but if you could have seen the impressed expression on our mortgage broker's face when he saw our credit ratings when we bought our first house a year ago, you'd know why it's worth it.