Way back in the 1920s, physics was in a state of upheaval (bear with me, this will make sense in a moment) because classical determinism was being eroded by quantum physics. Classical determinism was predicated on the idea that things were in one place only, had classical properties, and with instruments of sufficient precision these properties could be precisely determined.
Then along came quantum mechanics, which solved a lot of problems classical determinism was struggling with. In particular a gentleman by the name of Louis de Broglie came up with the idea that everything (particles, electromagnetic radiation) could be described by a wave function. This gave a probabilistic description of whatever was being studied, rather than a deterministic description. Much of the time, whatever it was would end up near the mean of the bell-curve distribution of possibilities, but at other times it could appear pretty much anywhere else on that bell-shaped (Gaussian) distribution.
Which brings us to sexuality. Very, very few people live right at the very ends of the human sexuality bell-curve, being entirely hetero- or entirely homo-sexual. Most folk are somewhere between these two extremes and depending on circumstances can be a little bisexual, quite bisexual, a lot bisexual, mostly homo/straight, and so on. By using deterministic language (straight/bi/gay) we make the error of forgetting that the real situation is much more probabilistic than deterministic. A woman who’s never considered herself bisexual may have an amazing night with two attractive lesbians, as did a friend of mine several years ago. A guy who considers himself straight may end up on his knees pleasuring his best friend after a traumatic experience and several pick-me-up beers. These events may or may not lead to anything else in future; the point is that our sexual responses are far more probabilistic than the old deterministic A or B or C thinking can encompass.
So basically don’t label yourself, just do whatever feels like the right thing to do at the time.