Hi.
No, no, I don't think you're homophobic. In fact, I admire you for being so thoughtful about your situation.
Lesbians, gays and bisexuals often say that "coming out" is a never-ending process. Since most people assume they are straight, unless they are given a reason to suspect otherwise, they constantly face decisions about whether to come out to people they meet. Imagine the exhaustion if a person felt obligated to explain she was gay every time she met someone new! Most people learn to pick their battles. The decision not to explain is often about time and energy management or, sometimes, about job security and personal safety, not about feeling ashamed.
Some of those same considerations may apply in your case. The relatives of lesbian, gay and bisexual people face a similar kind of "coming out" process. They also ask themselves, Should I tell my friends? My classmates? My coworkers? etc. etc. So you are not alone in your dilemma.
If you're interested in finding support around the various issues you face having lesbian parents, you may want to check out an organization called PFLAG (Parents, Families and Friends of Lesbians and Gays). Its mission is to help people deal with the often conflicting emotions they experience having a relative or friend who is gay, lesbian, bisexual or transgendered. You can find them on the web at www.pflag.org.
All the best to you and both your moms!