I did speech therapy in school and I didn't really find it that beneficial, other than learning to take a deep breath and slow down. I'm almost 30 and I still struggle with my speech but it's not as bad as it used to be. I could barely talk when I was younger and I understand high-school being tough as well. For me, it took getting on anxiety medication to kind of slow me down. I talk slower that the average person but I can communicate more fluently. Don't let other peoples opinion get to you. Not everyone is perfect and other people are probably not going to care but I know that doesn't make the speech any easier but people have their own issues, If they poke fun, theyre not the kind of people i would advise associating with. Stay strong in who you are and don't let it eat away at you.