Kylie Jenner feels like an ''old woman'' trapped in a young adult's body.

The 20-year-old reality TV star - who celebrated her birthday last week - kick started her business empire Kylie Cosmetics last year and has admitted she's had to grow up fast because she's had to learn how to handle her money and expand her brand.

Speaking in Sunday's (13.08.17) pre-recorded episode of 'Life of Kylie', she said: ''The majority of 19 year olds are still in the 'trying to figure it out' stage or in college. Me, it's like major responsibilities. I feel like a little old woman stuck in a 19 year old's body.''

And it's not just the financial side she's had to learn on the job as the 'Keeping Up With the Kardashians' star has has to work out who is trying to take advantage of her.

She explained: ''I definitely have like a lot of patience unless you're affecting my time. I had to learn how to balance between friendship and business, just trying to take on the boss role and standing up for myself, because people do take advantage of you.''

Kylie Cosmetics has exploded over the past 12 months and her products are in demand all over the world but, despite having a large team to help her deal with the business side of things, the entrepreneur makes sure she's hands on in every way.

She said: ''A lot of people think I'm not involved, but it's really important to me to have control over my own things.

And that's why Kylie was so upset when she found out that people had been making counterfeit lip kits and eye shadows with dangerous and harmful ingredients.

She explained: ''I'm thinking about all the kids thinking that this is my product and that it's safe. Their lips are swelling up and they're getting blisters and they're lips are getting stuck together because there's glue or gasoline in it.''