I will tell you some information on the 3 starter pokemon in Pokemon Crystal:

Chikorita:
Grass type
Lives in Grassland habitat
Weighes 14.1 lbs
87.5% male 12.5% female
Hight is 2ft 11in
Color is green

Cyndaquil:
Fire type
Lives in Grassland habitat
Weighes 17.4 lbs
87.5% male 12.5% female
Height is 1ft 8in
Color is Yellow

Totodile:
Water type
Lives on the water's-edge
Weighes 20.9 lbs
87.5% male 12.5% female
Height is 2ft 0in
Color is Blue

Here are some more information on them from their pokedex entries:

Chikorita:

It loves to bask in the sunlight. It uses the leaf on its head to seek out warm places.

Cyndaquil:

The fire that sprouts from its back burns hottest when it is angry. The flaring flames intimidate foes.

Totodile:

This rough critter chomps at any moving object it sees. Turning your back on it is not recommended.

I hope this helps for those few beggining trainers!