My 3 month old sleeps all night, has done from 5 weeks. 10pm until 6 then back to bed until 8 or 9. She stays downstairs with us until 10 and the evening is a nightmare. She's grumpy cries etc. Doesn't nap during the day at all. Should I try to change this? I'm terrified because I know I'm so so lucky that she sleeps.