hI, i'm brand new

Hi and welcome!! Click on settings then click on update diet/fitness profile. There you can change your birthday. Make sure you save your changes.

As a general comment I would say that I use this site through my Android phone, and found the bar code scanner useful in the early stages to simplify recording the foods I eat. For restaurants or home meals one must do a bit of research, of course. Since I have my phone with me almost always, I try to never cheat and always enter what I eat. Sometimes I go negative on the calories but I try to avoid that, it still happens.

On the exercise side I record minutes of elliptical and calories (from the display on the machine), and try to do some elliptical almost every day (I'm lucky to have the space at home and been able to afford one).

Since the exercise nets against my food, that helps avoid me going negative.

Although not specific to MyFitnessPal I find that trying to make each day similar to the last (i.e., so many calories remaining before lunch, so many remaining before dinner, so many remaining before exercise) it psychologically helps me. If I did it yesterday then I should be able to do it today. I can vary the foods but as long as the calories eaten comes out roughly the same, my today is similar to my yesterday. Of course it helps that I have a routine job and similar weekends. This won't work for everyone.