With regard to your court date, you should call the court and tell them about your conflict with school. They can tell you how to seek a continuance in the case, which will entail filing a motion (unless the local court allows you to do it by phone - I've never practiced there so I dont know).
With respect to the charge itself, when individuals possess a possibility of jail time, they are entitled to court appointed counsel. Given that this is your first offense, the Commonwealth will likely not be seeking jail against you (again, I've never practiced in Lynchburg, so I'm not sure what they do with first offenses) . If they do indicate they want to seek jail time, you have a right to court appointed attorney - ask for one (again, this is unlikely given that it is only a first offense).
If they do not seek jail time, you are only permitted an attorney if you retain one. If you cannot afford one, you have to go it alone, which is very difficult in a criminal case. Because it's a first offense, you are eligible for for a deferred finding. The court will usually grant it unless the Commonwealth opposes it or there is something unusual about your case.
If the court does not permit the deferred finding, then the Commonwealth will seek a conviction. A first offense marijuana is a Unclassified Misdemeanor with a maxim of 30 days in jail, 6 month license suspension in addition to other penalties.
In many cases a deferred finding is good because you avoid a conviction. But you are required to complete drug treatment classes, your license is suspended, and you receive a conviction if you mess up. Also, you cannot get the record expunged.
In some cases, you may not want the deferred finding because you can get a better result at trial. It sounds like there may or may not be search issues with regard to your case. You were approached because you were suspect of an offense, and you admitted to having marijuana. However, it sounds like they went pretty far in the search. This is an issue that needs to be researched and the outcome would depend on the officers testimony, how the Commonwealth does, and the particular judge you have.
That's the downside of not getting an attorney.
My suggestion would be to at the very least meet with a local attorney and see what they are asking pricewise. You want to avoid a conviction if at all possible. An attorney will definitely be helpful.
Best of luck,
James S. Abrenio
This answer does not create a attorney/client relationship, but is intended solely in the court of discussion. It is always my recommendation to retain an attorney whenever a court appearance is necessary. This recommendation is highlighted when it relates to an individual's criminal record.