I need Advice...

As you have done it before you probably also will follow the common guidelines of meeting in a public place and such, that by itself already should pretty much guarantee little can go wrong I must say. And dating over the internet is so common these days, it's not like every guy doing it is a pervert but many are just seriously looking for friendship or a relationship making the risks pretty much the same as meeting a guy in a bar or any place else if you ask me. If you are meeting in a public place you could probably try to reassure her by telling you will simply walk away if he looks suspicious to you or something.

Well, maybe you should tell her that the guy is ok. Maybe you should understand her point. She is afraid of you meeting strangers, no one knows what can happen. So, I think you should just follow your mother advice. But if you think the man is really ok... If you think there will be nothing wrong, then just tell her that and wait for her understanding.

At 21 I bet you have taken enough precautions, unless you have been allowing your mother to make decisions for you, which I seriously doubt you have. Putting aside her fear of the unknown, make sure you meet this person in a public place, and remain in public places. There is no reason for him to expect anything but a nice meeting so if he starts to pressure you for time away from others you probably need to dump him and head home. I never suggest anyone try to make their mother feel better. She is a big girl and should be able to control any trepidations she has without preventing you from being who you need to be, which is yourself and not her source of security,IMHO.