The 43-year-old actress - who is dating actor Justin Theroux - revealed she is happier than she`s "ever been" and hit out at "very narrow-minded" people who just assume the opposite due to her lack of kids. She said: "That doesn`t measure the level of my happiness or my success in my life, in my achievements, in any of that." Despite being three years into her 40s, Jennifer - who was recently reported to have said she wants to get married by the end of the year - admits she "feels great" and still gets "excited" every time she has a birthday. Speaking in an interview with `CBS This Morning`, she added: "I feel like I`m 30. I honestly didn`t start to feel my best until was in my 30s. Physically, I started eating better and taking better care of my body, in terms of being physical and exercise. "I think it`s important every year to celebrate your birthday and be excited about it. I`m 43 and it`s great!"