I haven't exactly been in your shoes as I haven't begun transition yet, but still dress masculinely and always have (I'm FTM). This summer, I took a class at a school far away from my college and actually found that the people at the table where I sat perceived me as male (I still use female facilities). However, at work, I'm known as a female due to my name and what's on my records so obviously I cannot be stealth there. This was the first time I truly felt "part time" as one gender or the other. Like you, I'm not particularly strict about pronouns (in the sense of "Oh god, i was misgendered"), though that can change.
As for you, I say do what makes you happy. You can always claim to be a butch lesbian/tomboy, whatever. No one is required to know more about your life than you're willing to give them. Granted, as someone who was designated male at birth, it may be hard to pass as a lesbian, but I imagine HRT (if you go that route) would make it easier. Androgyny isn't any easier to be than say FTM or MTF. You have to find your comfort zone and learn how to exude yourself in a way that will make people see you as close to the gender identity as you relate to as possible. Something I've learned along the way, though, is that gender identity is in the eye of the beholder. As long as you're not in any danger, experiment with what feels right in terms of your gender. Your first and foremost goal should be to become happy in the body that you have. Worrying about people taking you seriously should be lower on the list.
