I would have writen :
What´s up boys and girls?!
I have created this topic to practice a little bit of english.
It´s a mean to not lose what we have learnt at school.
This discusion doesn´t need any particular level in english. Everybody can participate!
Just try and enjoy it ; )
You use too much -ed, even when you don´t have to do it. But it´s not so bad, don´t worry.