DD's org made all 14's that aged up start emailing coaches. As a sophomore DD now has about 10 coaches that could recognize her and another 10 that know her name. Now is the time to get started. In fact you are a bit late.
My $0.02....most major D1 schools do the majority of their recruiting at 16U. Smaller D1, D2, D3 and NAIA do a lot of their recruiting at 18U, but still watch 16U too. I think a lot of it depends on the schedule of the teams you are considering. What showcases and tournaments are they playing? I would give preference to a good 16U team that will play in good showcases vs. an 18U team, especially if your DD is a '99. Is she a 2017?
To be honest, unless she is playing for one of the top TB teams, it doesn't matter.
The recruiting process is:
1) You write the coach, tell them about your DD.
2) Provide a video
3) Ask the coach to come watch a game.
The odds of a coach going by a game and saying, "She is for me!" are pretty low.
You must live on the coast. The 16u teams in my neck of the Northeast are really good and could beat a lot of 18u teams.In the Northeast, the best 14-15-16 year old players play 18U. 16U here is for girls who are unable to cut it at the 18U level. I recognize that this is not the case in other parts of the country. It's tough to find competitive 16U tournaments/showcases at all here.