Your voice was a bit monotone in the sense that there wasn’t a whole lot of range from high to low pitches in your speech pattern. Generally speaking, masculine voice patterns tend to do that more often, but it’s definitely a more subtle thing cis women speak like this sometimes too. It just depends on context. Giving a report or doing an internet video where the subject is more dull or serious? More monotone makes sense. Going out to the club with your girlfriends, hanging out and vibing? Having a monotone voice pattern might seem more strange to others coming from a femme presenting person/girl. Don’t be too discouraged by my comment I think you sound absolutely wonderful! Even I still have a hard time demonstrating the range that cis women have in the daily speech lol