According to the previous answers it alone shouldn't affect you; however, keep in mind that you turn 21 in less than 3 years (time for ticket to get off of your insurance & employer to see) and you are presuming that you won't get another citation during that time period. Additionally, CDL's are governed federally and other States may care. Bottom line, it wouldn't hurt for you to investigate various options other than just pleading guilty, namely, contacting a local attorney who could help you or even the Court for options or some form of deferral. Best of luck.
It depends on how many tickets you currently have. I had a CDL for quite a number of years, and I can tell you that you don't want this ticket on your record. When you apply for a job with truck carrier companys, they will check your driving record to see if you are insurable; and the more tickets you have the more they will have to pay to have you insured. Therefore, I would very strongly suggest hiring a lawyer, and having him deal with this for you. It'll save you headache and make getting a job easier down the road.
My office handles these, give me a call if you like and we can set something up.