Hi and welcome to the forum!

At 2 inches your turtle is most likely still just a baby. They're really cute at that age!

There's a lot of good information on this website. Here's the link to the nutrition section...
http://www.redearslider.com/index_nutrition.html
Generally the rule of thumb for feeding babies is to give her enough pellets that would fit inside the space of her head (not including the neck) if it were hollow. Do this once a day and add some vegetables (Red or Green Leaf Lettuce, Romaine, Dandelion leaves, etc) every day. Remove any uneaten pellets before they disintegrate or get sucked up by the filter and remove uneaten lettuce by the end of the day. A good variety of food and veggies is beneficial. The nutrition link above will list a good variety of foods to choose from.
Also make sure to read the section on Basic Care and especially what's mentioned here...
http://www.redearslider.com/startup.html. You want to make sure you have everything you need to keep your turtle healthy and happy.
Feel free to ask anymore questions after you've had a chance to read the info on the web site!
