My ortho told me i had a class iii severe malocclusion on the right side of mouth and a class i on the left side of my mouth. will this need surgery or will elastics fix this?

Your orthodontist is the best one to ask this question and any others that you may have. They have examined you, taken radiographs, and made measurements. A consultation with an oral surgeon may be in order. Together, as a team, they will give you that picture perfect smile. It is not possible to advise you further, sight unseen.

To answer your question requires a full diagnostic work up. Your question doesn't answer dental? skeletal? both? severity? problems in vertical and/or transverse planes of space or just sagittal? Have your specialist Orthodontist do full analysis. Referral to Oral Surgeon may or may not be required. In a 19 year old non-growing female elastics alone will not correct skeletal abnormalities