The old advice is “Write what you know.”
That’s a misleading phrase, and it stymies many a beginning writer. The actual phrase should be “Write what are willing to learn about exhaustively.”
You don’t have to experience skydiving to write about a skydiver … but it helps. Any experiences you have that are similar or identical to what the character is going through are experiences that will enrich your book. If you’re not willing to learn skydiving, perhaps you could ride a roller coaster to feel that stomach-churning weightlessness. Or read exhaustively about the experiences of people who do skydive.
The more research you do, in other words, the better your writing. And, of course, the more research you do, the more you know. So … Write what you know.
Use the ordinary experiences you’ve had in your writing as well. How does it feel to wake up on a crisp morning in a camping tent? What do the mountains look like on a Winter afternoon? How does it feel to wear an evening dress or a wedding gown? What does a family football game feel like?
The more personal you make your character’s experiences, the more vivid they’ll be for your readers. Just don’t write exactly what happened at your cousin’s wedding, or your relatives will recognize themselves and you’ll have a family argument to include in your next novel.