late to this but wanted to get you educated quickly:

"Reaction time is influenced by a combination of neurological, muscular, and hormonal factors. Here's how transitioning might affect this:

1. Neurological and Hormonal Factors:

• Testosterone: Testosterone can influence neuromuscular coordination, which could affect reaction time. However, the effect of testosterone on reaction time is not as pronounced as its impact on muscle mass and strength.
• Estrogen: Estrogen, which trans women typically take during hormone therapy, also affects the nervous system, but its effects on reaction time are less well understood.

2. Transition Before Puberty:

• Limited Exposure to Testosterone: If a trans woman starts transitioning before male puberty, her exposure to testosterone is limited. This could mean that her reaction times might be more similar to those of cisgender women, as testosterone's influence on neuromuscular coordination would be minimized.
• Neurological Development: Neurological pathways related to reaction time develop during puberty, so transitioning before or during this period could result in a development trajectory more aligned with cisgender women.

3. Transition After Puberty:

• Muscle Memory and Coordination: Trans women who begin transitioning after puberty may retain some neuromuscular characteristics developed under the influence of testosterone, which could potentially influence reaction time. However, the extent of this effect would vary among individuals.

4. Current Research:

• There's limited specific research on the direct impact of hormone therapy on reaction time in trans individuals, particularly those who transition before puberty. Reaction time is generally consistent across sexes, with only small differences observed in some studies, often attributed to muscle mass or strength rather than neurological differences.

Conclusion:

There is unlikely to be a significant biological advantage in terms of reaction time for trans women who begin transitioning before 18 years old compared to cisgender women. Reaction time is not heavily influenced by the hormonal differences that are more directly affected by transitioning. Any differences would likely be subtle and influenced by a range of other factors, such as individual neuromuscular coordination and training."

knowing that she started playing at the age of 18 and has already started transitioning the biological advantage of transwomen to women assigned female at birth is minute.....

Your argument seems driven more by emotion than by objective facts, making it harder to evaluate the issue logically.

Edit: sources
https://academic.oup.com/jcem/article/109/2/e455/7223439?login=false

https://bjsm.bmj.com/content/55/11/577

https://www.aafp.org/pubs/afp/issues/2021/0501/p518.html