everyone at NA is generally really welcoming but it differs. i went to one in rehab where everyone was really cliquey and no one talked to us.
i'm kinda lucky in the i first went to NA while i was still using and i was a permanent mess. smoking crack in the toilets or nodding out. i was never pulled up on it even though now i consider doing that unacceptable, only ever treated with kindness and concern. i have no idea what anyone said the entire first 6 months. BUT one guy at NA convinced me to go to rehab. i didn't believe i was bad enough to go to rehab cos i wasn't homeless or injecting in my groin or whatever. there's quite a high chance i'd be dead if i hadn't gone to rehab cos i was pretty reckless with iv use. so i consider NA to have saved my life.
so, i was just oblivious when i went which did away with any social anxiety. when i came out of rehab, 2 stone heavier and no longer half dead looking, everyone at the meetings was so pleased and it gave me a massive boost. actually now i get more social anxiety than i did at the start and i don't really share in meetings where i don't know everybody anymore because i feel uncomfortable.
try a few different meetings cos there are different vibes, there are some i actively don't like and others i love.
actually someone at a meeting today said something pertinent to this- if there was a room full of people you didn't know with a table piled with your DOC, would you go in and use with those people? i certainly woulda, and wouldn't have thought twice, so why not go and recover with people you don't know?
there are some weird bits to NA, the serenity prayer at the end still makes me cringe every time and i've been going a year. it really really isn't religious, but a lot of people talk about god quite freely. and a lot of people just share 'i was fucked. this program saved my life' without really saying anything to substantiate it which pisses me off cos it gets boring after the hundredth time, and doesn't help newcomers to just be vague and arselicking.
you will get phone numbers of men/women (depending on if you're a man or a woman) and they really will mean it when they say use them. i've actually made a couple of decent friends there now too even though when i first went i thought 'no way do i wanna hang out with these losers' as if all the crackheads i was hanging out with weren't losers. ha.
at the end of the day, you have nothing to lose and a huge amount to gain, so try it. and if you think 'this isn't for me' try again a few more times.
i have my doubts about a lot of what they say but what is a fact is that its the only place i can go any night of the week and talk to a variety of people who have used like me and lived to tell the tale, and that is priceless.
sorry for the long ramble, i hope that kind of answers your question and if you have anymore questions let me know.