I have astigmatism and im 19 years old and have weak eye sight since I was 13 years. Is laser surgery possible?

Possible. Nearsightedness, farsightedness and astigmatism can all be treated with laser vision correction (lasik, prk, lasek). The important question to answer is: how well can your eye see with contacts or glasses? Lasik can allow you to see without glasses what you did with your best lenses. If you had weak vision even with lenses, lasik will not improve it. A lasik doctor can let you know for sure.
Maybe. Depends on what the best potential vision is and if it's worth laser surgery correction (i.e. Benefit over risk). Sometimes amblyopia can occur if one eye was always weak, and it'll stay that way since it was a developmental problem (no way to correct that currently).
Maybe. You want to be sure that your eyes are stable and not changing anymore before you consider refractive surgery. Also if you wear contact lenses, be sure to check with your lasik surgeon as to how long to leave them out before measurements and surgery.