I first want to say congratulations for finding love and I hope it is mutual!
Straight women don't fall for other women. They love women fiercely but with a friendship love not a romantic erotic love. Women who are attracted to other women fall in love with other women and all of those types of loves show up--friendship, romantic & erotic.
Do you think heterosexual people who fall in love when they are in high school think to themselves, "Am I even straight since I married the first man I fell in love with?" It sounds ridiculous right? I'm not making fun of you I promise. But queer people are often forced to ask themselves questions that heterosexual people never ask because we think there is something inherently wrong with us. There's nothing wrong with us. We love who we love.
I want you to never question your love because you think something is wrong with you. Whenever you feel yourself questioning your love ask yourself if you've ever heard your straight friends & family ask themselves the questions you are asking. More than likely not. Your straight friends are asking questions more about the person. Is this the right person for me? Can I see a future with this person? Is this real love or am I just sexually attracted to them? These are the questions you should be asking yourself.
Your gayness is not determined by how many people you've loved. Every person who wants a relationship is looking for that ONE person to build a future and a family with for the long term. Challenge yourself to shift into asking those questions of the person on the other end of your love.