Nicky Hilton Rothschild says her younger daughter Teddy, 3, "definitely gets a lot of hand-me-downs from her big sister" Lily-Grace, 4½
Nicky Hilton new children’s clothing line
Credit: Camraface/Early Morning Riot 

Nicky Hilton Rothschild is sharing clothes shopping hacks for parents to keep up with kids who are "growing so fast."

The fashion designer recently launched her collaboration with Dotty Dungarees that features a collection of spring outfits for girls ages 6 months to 7 years old, and also available on Maisonette.

In a new Q&A on Dotty Dungarees' blog, Hilton Rothschild, 37, says she feels as if she's "constantly" buying new clothes for her daughters, Theodora "Teddy" Marilyn, 3, and Lily-Grace Victoria, 4½, whom she shares with husband James Rothschild.

"I feel like I'm constantly shopping because at this age, my girls are growing so fast," she says, adding, "I always buy them a size up. Both of my daughters are very girly so they love dresses, which makes getting dressed a bit easier. I'm not constantly searching for tops and bottoms. Teddy, my 3-year-old, definitely gets a lot of hand-me-downs from her big sister!"

The mom of two adds that she always aims for "comfort and quality" when finding clothes for her girls, explaining that she likes dungarees because "there is something so sweet and innocent about them, not to mention how practical they are."

Want to get the biggest stories from PEOPLE every weekday? Subscribe to our new podcast, PEOPLE Every Day, to get the essential celebrity, entertainment and human interest news stories Monday through Friday.

Nicky Hilton new children’s clothing line
Credit: Camraface/Early Morning Riot 

Hilton Rothschild recently told PEOPLE that her daughters, who are "very girly girls," gave their "stamp of approval" to Mom's new collection, especially the dresses. And the businesswoman has no plans to change up how she outfits her daughters for their everyday life.

"I love a pair of dungarees; it's such a classic staple. And I think today, a lot of parents are dressing their children in these hip, miniature adult outfits, which I'm not really a fan of," she says, adding, "I think children should dress like children."

Hilton Rothschild also shared that her kids are beginning to develop their own senses of style, playing dress-up and creating imaginative ensembles.

"Both of my girls definitely love dressing up, and it started very young, at like 2 years old," she explains. "They love costumes and they love dressing up as princesses. ... Their bond is so sweet. A sisterhood bond is so special, and I love seeing that with my girls."