Virgin with a tight vagina. Gyn says even swab is difficult to enter. Worried about a painful 'first time.' should I drink? Will I bleed, tear much?

Use a tampex. When on your period use a tampex and then consider inserting with vaginal lubricant . Often time people have vaginismus (spasm when entered) and it is a strong muscle tensing up due to anxiety. If you continue to be worried your gyn can help you stretch it a bit.
Honor yourself. Absolutely do not drink in order to have intercourse- ever! there are other ways to be intimate if intercourse is painful- find the right partner and this will be a non-issue. Ask you gyne for 2 resources: 1: estrogen vag cream to help open the introitus. And 2: referral to pelvic floor physical therapy. There is no reason this can't be addressed appropriately, respectfully and humanely.