We started our son in 1st grade as well. He had been diagnosed just shy of his 5th birthday but we waited due to OUR fear. Our son struggled and had a horrible 1st grade start. With the help of his teacher we started meds. It made things so much better for him. Unfortunately he could NEVER live the labeling from other kids/parents go away. I still carry the guilt that due to my fear my son suffered. You are doing the right thing.
Starting meds is hard and so isn't finding the right med and dosage. Many here have been through it. If you need any help, please let us.
Things did get better for my son once he left elmentary and went to middle school in 6th grade, but it sure was a long road we were stuck on. I hope things are better for your daughter. Social is the constant problem for our adhd'ers. Again, you are doing the right thing!! 
Hello and welcome to the board!
How old is your daughter? I think the guilty feeling about feeding our kids drugs is completely normal at first. None of us wants to have to medicate our kids. But for most of us there really is no choice.
With my son I new something was not right before he was even a year old. He got diagnosed very early because he's sooooooo severe (just shy of 4) and it was actually a relief for me! It was like everything I felt in my heart was affirmed and it confirmed that my little boy needed help. Medications have literally changed his life and mine! He will never be "normal" but at least now he can function in this world and be happy. He couldn't do that before.
You've come to the right place. We're all here for each other! There is soooo much information and support on this board. Keep coming and please let us know how the meds work out. Good luck! 
Well if you get the medication correct she will be happier, have more friends, more self-esteem! Most of this will be possible because she will be able to regulate her behavior like she's never been able to before. The end result is that she won't be in trouble as much! 
Did she start the meds today? How did it go? What is she on?
Troll!