Can I achieve +6 diopter with glasses if I am currently +6.5 so that I can get LASIK?

Depending on the laser your ophthalmologist will use, LASIK is usually only approved up to about +4 to +6 diopters, but the results are much better at 4 diopters or less.  Additionally, farsighted or hyperopic LASIK tends to regress over time, so even if your ophthalmologist considers this procedure for you, it's important to understand that the results will not be permanent and you will either be back in glasses or require periodic enhancements throughout your life.  Hopefully, as our Excimer laser technology advances, extremely farsighted patients like yourself, will see more benefit.

In my Baltimore Maryland practice, I am comfortable treating farsightedness up to 5 or 5.5 diopters, if the corneal shape and thickness will allow it. I use a femtosecond laser to create the flap(Intralase) and a 400 hz Wavelight Allegretto excimer laser, which I think is the best laser platform in the world.  If the prescription goes above this, I will either recommend a lens based procedure(clear lens extraction, refractive lens exchange) or defer the patient for future technology. Outside of the US, there is currently an Intraocular Contact Lens that is available, but it has yet to be FDA approved in the US. If I were you, I would get several opinions and, due to your youth, proceed slowly.