There are several reasons why your lawyer feels that waiting is in your best interest:
In the first place, delay is always a friend to the defense. Over the span of time, witnesses forget things or can move out of the area and turn out to be unavailable. Evidence grows stale. Secondly, assuming you may want to resolve this case with an offer if you get the right one, the older a case gets, in my experience, the less interested the prosecutor is in it. You may be able to get a better deal just because the DA wants the case finally off of his desk. Also, you are clearly at liberty, and if you are convicted of this charge after trial, you will likely be sentenced to some jail time. And finally, there's a right to a speedy trial, and somewhere along the line, assuming that it's not the defense that is causing the delay, you may be able to get a judge to dismiss this case on speedy trial grounds.
Speedy trial laws are more complicated than they sound in that the US Supreme Court has provided a balancing test for when it's appropriate, and there is no hard and fast time that it must be granted. However, under South Carolina law, a cases that has not not been resolved after about 2 and 1/2 years may be dismissed unless the prosecution can make a showing of good cause that such a delay was necessary. Also, a South Carolina case still pending after 4 years post-indictment, may be dismissed too.