Certainly going to be an issue. I would prioritise the first try out of your preferred club, at least get a gauge on other talent, coaches etc.
Depending on the talent/aspirations of your young athlete, priority might be getting on a team, full stop. I know last year, clubs at U14/16 cut a lot of kids. Devastating for all concerned.
Some clubs go 10 deep, many to 5-6. And all clubs prioritise existing rep players for precious roster spots. And some prioritise bottom age over top age too when it comes to transfers/new.
Unfortunately, you do need to keep options open across multiple clubs if you're new to rep. I saw a young athlete trial with one club only, made it to last trial and were cut, with no other options so missed another year of chance to play rep.
May want to consider Blackburn and Doncaster, they tend to not be "destination" clubs, so might be easier to get a roster spot. Nunawading girls are super strong and I know Nunawading boys cut athletes who made number one/two teams at other clubs last year.
Good luck