Except gender is a much less mature topic than sex and sexual attraction, something that should be taught around 5th grade if not earlier, before children have confusing feelings and their bodies undergo confusing changes. The media atmosphere already leaves impressions about sexuality in the minds of children much earlier, so there isn't much harm for parents or teachers to discuss the topic in a much healthier way.
Gender on the other hand is something impressed upon and experienced by even toddlers, so the topic of gender isn't all that mature, it's only treated as mature because of the social taboos regarding trans individuals.
My problem with Lae'zel is that she shares too many major story beats with Shadowheart. But individually they are good characters and we aren't spoiled for choice with 6.5 origin characters and a few more plot relevant companions. Her story works well for a Gith and it's good that we have a Gith companion option with how relevant the illithid are to the plot.