Water Baptism
More properly called 'believers baptism'. Baptism - a full immersion. For Christians it symbolises a cleansing a washing away.
For us it means a full immersion in water - we put you under - yes, all the way. Not like a sheep dip to ensure you don't have any bugs, but more to symbolise how you have 'sunk' yourself completely into following Jesus.
It says that you have 'died' to your own way and now have committed yourself to following Jesus' way for your life.
It's called a 'believers' baptism because it's not just a 'get out of hell free card' - it's not something we do to infants just in case! We only do it to those who believe in Jesus, who have made a clear choice for themselves.
No it is not only limited to adults because many children can make a fully valid choice to follow Jesus for themselves. All that is required is that you have made a personal choice to follow Jesus and have given your life to him
You do this by asking him to be the 'boss' of your life and by asking him to forgive all the things you have done which would cut you off from him - otherwise known as 'sins'.
1 Peter 3:18
'In it only a few people, eight in all, were saved through water, and this water symbolises baptism that now saves you also - not the removal of dirt from the body but the pledge of a good conscience toward God.'