solid foods?

i think it may be getting close to the time to start solids. my plan was to wait until closer to when caleb was 6 months, but i may not make it. he's gone from eating every 3.5-4 hours to eating every 2 hours. and he's gone from waking up once at night (after sleep 7 hours) to waking up at least 2 times (every 3 hours or so). he just never seems full. and i think he's doubled his birth weight, so it may be that time. i'll be asking his pediatrician about it when i take him in next friday for his 4 month appointment. part of me is excited for the possibility of this new step and part of me just wants to hang on to my little baby a while longer.