I see no problem with changing the gender. Sometimes when reading a series I wonder what would change if one or two characters were female or male, most of the time, not much would change, other times some things would look differently than before. Like take Deku for example, who has a real lot of fanart where he is shown as female, if he was a girl from chapter 1 what would change? The personality would still be the same ofc, but for example Bakugos bullying on Deku could be seen under a different light, heck he might even get made fun about him being into Deku because he is so hard to "her" or people would stand up more against Bakugo saying that he goes too far against a girl for there is in general a difference seen between how a boy can treat another boy compared to a girl.