33 y/o F. Homocysteine 11.45 Heterozygous MTHFR c677t. Is my homocysteine too high? Noticing different lab's values vary greatly, and are conflicting

No. It is border line. Don't compare normals in various labs. Only ur level to that lab. normals. Also check ur vir b12, folic acid and pyridoxine levels. Don't dx ur self. If early stroke or other signs read in web then see a specialist may cardiologist .