I have no organ involvement in my lupus but its just a matter of quality of life, am I putting myself at great risk by starting methotrexate?

Some risk. Methotrexate (mtx) is not a great risk but there is some risk and you absolutely must use contraception if you re sexually active. If you have failed Plaquenil and you still have serious quality of life issues such as fevers, fatigue, joint pains, etc., it may be good to consider mtx or benlysta (belimumab). Pain and fatigue can change your social life, home life, sex life, and work life.
Not necessarily. You are lucky not to have internal organ involvement (for those in the us, nba legend kevin mchale lost his 22 yo daughter today from lupus), but Methotrexate does not significantly increase health risk as long as you maintain good followup with your rheumatologist. I would further argue that Methotrexate is a small price to pay to ensure that your lupus does not worsen.