Congratulations on coming out to your parents and siblings. Coming out takes a good deal of strength and courage. Coming out to your immediate family is a momentous step. And, as you share this aspect of your persona with other people, you will continue to expereince "coming out moments". Know that coming out is completely your decision. You decide how, when, and to whom you share various aspects of your life.
Thomas, Thanksgiving could provide the opportunity to introduce your boyfriend to your family. Holidays can be a bit stressful. So, if you want to avoid making Thanksgiving a massive coming out day, you could approach your relatives before the holiday. You could visit or call them to let them know. You could tell them you are excited to introduce them to this great young man, your boyfriend.
Yesterday, 11 October was National Coming Out Day. If you want, you could relate your coming out to this day of observation. You could extend this to the weekend to inform the rest of your family. There are many ways you can come out. Again, your comfort and safety are the guiding principles. You might find it helpful to write out and rehearse things you might say. You might find the Human Rights Campaign’s “Resource Guide to Coming Out” at http://www.hrc.org/documents/resourceguide_co.pdf helpful. In addition, on http://www.amplifyyourvoice.org/youthresource/comingoutquestions you'll find an article called "Coming Out to Your Parents: Questions to Think About" which may be of help to you.
Parents, Families and Friends of Lesbians and Gays (PFLAG) is a great organization, made up mostly of parents, which supports LGBTQ people and works to help parents and others to become more supportive and accepting of their loved one's sexual orientation/gender identity. On their website at www.pflag.org click on "Get Support" then click on "For Family & Friends" where you'll find the pamphlets "Our Daughters and Sons: Questions and Answers for Parents of Gay, Lesbian, and Bisexual People" and “Frequently Asked Questions about GLBT People,” which, if you’re comfortable, you can share with your family members/friends to help them become more understanding and accepting of you. PFLAG also runs support groups where parents and others can discuss questions and concerns they have about a loved one's sexual orientation and where LGBT people can discuss issues they're having with people in their life. On their website, you can search for a chapter near you. If no chapter is near you or if your family members/friends won't attend, you could still contact the nearest chapter and get support and learn ways to help them become more understanding of you.
If you want to get some peer feedback, try TrevorSpace at www.trevorspace.org. It’s the Trevor Project's safe, online social networking site for LGBTQ young people ages 13 to 24 their friends and allies. It's a great supportive community where you can connect with others who might have had or are having the same questions that you’re having about your sexuality/gender identity.
Thomas, you have demonstrated a keen level of awareness. However you decide to proceed, your thoughfulness will serve you well.