Besides acceptance, if I were a parent to a trans child I would be opinionated about them starting puberty blockers at the very least.
Reading threads on /r/cisparenttranskid, I notice a lot of trans youth are insistent they don't want any medical transition steps (even puberty blockers), and then once they have been a few years into puberty, predictably the dysphoria hits bad and they suddenly have distress and realize they need medical transition.
It's much, much better to avoid needing to medically transition after puberty, a lot of harm can be avoided by not going through the wrong puberty.
Puberty blockers are safe and reversible, and it's the true "neutral" choice (compared to either letting them go through the wrong puberty naturally, or starting cross-sex hormones to start going through the other puberty).
This is aimed at reducing harm and is backed by the evidence.
Medical & social transition for minors is recommended by all major pediatric and medical associations.
Here's a literature review of the studies done that found transitioning improves well-being: https://whatweknow.inequality.cornell.edu/topics/lgbt-equality/what-does-the-scholarly-research-say-about-the-well-being-of-transgender-people/