Junior Tennis Development: When to Start Competing?

My daughter just turned 10 and has been taking tennis lessons for about 18 months. Her coach says she's progressing well and suggested she might be ready to start competing in local tournaments.

I'm excited but also nervous about this next step. Some questions I have:

Competition Questions:
• What age is appropriate to start tournament play?
• How do I find local junior tournaments?
• What should I expect at her first tournament?
• How can I support her without being "that parent"?

Development Concerns:
• Will competition put too much pressure on her?
• How do I keep it fun while being competitive?
• Should we increase lesson frequency?
• What about mental coaching/sports psychology?

She loves playing and practicing, but I want to make sure we're doing this right. Any parents who've been through this journey have advice?

Also, are there any good resources for junior tennis development that you'd recommend?

Thanks for any insights!