"Day at Mommy's," Kylie captioned her bikini photo shoot

Kylie Jenner is spending her last day as a teenager by the pool.

The soon-to-be 20-year-old, whose birthday is Thursday, shared a set of bikini-clad photos Wednesday on Instagram with the caption, “day at Mommy’s.”

Jenner relaxed poolside in a nude-colored two-piece bathing suit with her long tresses tied in a bun. On the eve of her birthday, the Life of Kylie star has much to celebrate, as it was reported on Wednesday that Jenner’s extremely lucrative cosmetics empire, Kylie Cosmetics, isn’t just profitable, it’s blowing past other competitive beauty brands in the industry to rake in $420 million over the last 18 months alone.

Momager Kris Jenner proudly told Women’s Wear Daily that if growth continues at this rate, her daughter will have a billion dollar business on her hands by the times she’s 25.

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To ring in her 20th birthday, the youngest KarJenner released a special edition birthday collection, which made $10 million in just one day — her second-highest sales day ever.

Also in that WWD interview, Kylie’s plastic surgeon credited the Keeping Up with the Kardashians star as one of the reasons there’s been an uptick in copycat procedures among young women.