Re: nerves, stress, unsure!
I was also in a similar position as you, I would recommend that you talk to your mom directly. Its your mom, you should be able to talk to her comfortably. Don't say that I like this guy and such. Start of with "Ami, I got a proposal from a guy, i know him through friend/school etc. I told him that he would need to properly send the rishta and talk to my parents" and see what she says?
she will probably ask questions about him like what does he do, how old is he and such? Answer casually don't let her feel that you are already head over heels for this guy.
Since your mom wants to get you married soon, she will probably ask you to have the guy's parent contact them and such.
Our parents wants the best for us, they are not out to get us. if the guy is a suitable match for you I am sure they will never say no.
Just talk to her.