Is My Brain Ageing?

I discovered that for me as a 23year old male, my brain is not at it's peak performance...

For example, an old issue of 8 Days said that the best way to test your brain's seniority is to recall what you had for breakfast, lunch and dinner --- yesterday.

Now here's some of my very own Litmus test to see if your brain is ageing...

1.) How many contact numbers of your friends do you actually know and remember by hard (Auto-dial doesn't count :P)?

2.) How much money did you spent on the things you bought 2-3 days ago?

3.) When is your spouse's/parent's/child's birthday?

4.) What was the first sentence you learnt to speak when you were still young?

5.) If 100 is an even number, what are the previous 10 odd numbers before 100?

*I'm a cow, hear me moo...