No, she's just gay.
Why does everybody assume gay women are these super effeminate types? You have lesbians, tomboys, butch, and dykes.
Brittney is what most would consider a butch/dyke, a term that was popular in the 90s and 00s to describe a gay woman who is more on the masculine side rather than the feminine one which is the type of gay woman who goes through drastic measures to sound like a man but also carry herself as such in terms of how she dresses, etc.
In other words, she's the “man” in a lesbian relationship. Y'know, when it's time to have sex, she's “the one that pegs, not get pegged”.
In the 2000s, terms such as Butch and Dyke were popular to describe these types of gay women, but in the 2010s and now the 2020s, I guess the term has become offensive or has lost traction in the mainstream.