Hi there, Renee, @outlawedpipes (what an intriguing ID name; bet there’s a story!), and WELCOME to Postcrossing!
I was new 2 1/2 years ago, and felt some similar feelings.
Hope these thoughts help:
- Have fun; do your thing. While profiles include ‘wish’ lists, these are not demands; just suggestions. Most Postcrossers seem to like the note written as much as anything because we are interested in other people/places
- This is a community of communicators; not a facilitator of collections. If you have something that matches the ‘wish’ of a collector (stamps, postcard series, etc.), great. If not, send your card from your creative heart.
- To save money, you can set your settings (at the bottom of Edit profile) to ‘most popular’ countries; you’ll likely get a lot of US addresses;
- Do you want my list of oopsies from my early days and weeks?
We all make mistakes, learn from them, move on, then have even more fun. 
- If you break a rule, don’t feel bad. I’ve broken one or two, in error; someone redirected me and we all moved on. Nobody lost an eye!
- Budget your time and resources. Not everyone likes washi or decoration on their card, so I save the time and creative effort for those who indicate a like for it.
- One of my favourite Forum activities is Month of Letters. But maybe one card a day will be a bit much for you, given how busy you are?
As others have noted: participate and give what you can, when you can. No rush. No deadlines. No hassle.
Have a jolly wonderful time!