Kim Kardashian's got a year to get her weight on check! But seriously ... she looks amazing, why would she want to lose weight?!

The just-turned-39-year-old says she's prepping for next year's big 4-0 by hitting the gym night and day. Kim says she's gained 18 pounds in the past year and she's not comfortable with that.

The reality star posted a video of her night workout with trainer Melissa Alcantara to her Instagram Story and said, "To feel good, I just want to get it like, a really good goal weight and so that means working out at all costs. It’s my eating. I work out but it’s like, my eating. But Melissa and I have a major goal for by the time I’m 40."

Last year Kim's fam was worried she'd gotten TOO skinny but Kim says she felt great, "I’ve lost 20 pounds and I’m really proud of that. I was almost 140 forever and now I’m, like, 116 and it just feels good,” KKW Beauty founder told E! News in August 2018. “I didn’t see results right away, but when you stick with something and you’re consistent, you will. So, I love it.”

And remember when Kendall expressed her concern about Kim's weight loss on Instagram last summer? To which Kim replied, "What? Oh, my God, thank you." Of course she got backlash for that, but hey, if that's how she feels her best and she's being healthy, then more power to her!

Meanwhile, a little Halloween throwback ... Kim posted pix of her "West Worms" family costumes after last week's holiday. I mean ... great get-ups, but not exactly "cute" -- more like scary for little kids, right?!