Chadwick, who pocketed $500,000 for winning the series, won the event opener at Hockenheimring in May and the third race at the Misano World Circuit in June to set up her Championship success.
Chadwick, though, knows there are challenges ahead as the last woman to compete in Formula 1 was Italian Lella Lombardi in 1976.
“I’m under no illusions as to how tough it’s going to get,” she told Reuters.
She added: “If you look at all the drivers who’ve made it into F1, they’ve all come with significant backing. Whether that’s personal or through sponsors or a team, none of them have paid their way scraping the barrel.”
Chadwick also created history last year by becoming the first woman to win a round of the regular British Formula Three Championship while she is also a development driver for the Williams F1 team.
She is likely to return to the W Series next year, but she is setting her sights on “greater” things.
“I want to do as much as I can… my overall aspirations are much greater than just this, than the W Series,” she said.
“I want to go on and achieve a lot in the sport. Next year will be preparing myself in the best way to do that.
“This year’s been great, but really I need more racing under my belt to level up with the top guys that are out there, and hopefully next year can allow me to do that.”