Well in a sane world, there is nothing wrong with visiting an online friend at home for the first time but it's quite unfortunate that we are in an insane world where every stranger has the potential of being a good guy or a rapist, kidnapper or a murderer.
Visiting an online friend at home can be very risky especially if you do not trust the to a large extent. People can be saints online but demons in reality so you've got to be careful with whom you put blind trust in when visiting for the first time.
Furthermore, you have to be prepared for the worst to happen so that you'd not end up being victim to certain social vices.
Conclusively, if you can avoid it, you can meet for the first time in a public place and if you must see the person in his home, go prepared