If my sciatic nerve is being pressured by something in my lower spine and cannot touch my toes with my legs straight should i get surgery at age 20?

No: It sounds like you have had a tough time with sciatica and have poor flexibility. It appears that you need aggressive physical therapy and good medical management by a physician to help the problem. Its not clear if you are already being offered surgery or not. Surgery is not the answer for true sciatica. Look into a technique called neural flossing with a physical therapist.

Treat conservatively: Most of these problems are self limited. Avoiding surgery at 20 would be best. Only if radiating leg pain persists beyond 6 weeks should you consider consulting with your physician.

Be cautious: Back surgery is to be avoided in almost all situations, as the risk of a bad outcome is far from rare, and at your age a very bad idea. However, if you suffered progressive weakness with muscle atrophy or progressive loss of sensation, associated with uncontrollable pain, surgery would be an option. If you suffer bladder dysfunction, surgery is likely mandatory.