Since you're asking, you're definitely not ready. Learn a projects formatting style for the code, work on open issue, submit patches, listen to all critiques and criticism.
Submit and the others will say when you're good. If you want to learn code correctness and proper security of code, study and go through OpenBSD's code. You could read the code for openNTPd and the code for OpenSSH, then move on to reading kernal code for OpenBSD.
You get over yourself and if necassary you give them your phone number. Using whatever app is personal preference and you can choose to say yes or no to using saidapp, but random strangers don't care enough to obsess over getting someone's contact into. That's what number block is for.
Anyone who thinks if a stranger gets their number that stranger will now stalk them, that person is a delusional narcissist.