First off, thanks so much for the compliment :) you are very sweet! <3
As for the posting online question, don’t worry! It’s normal to have reservations about putting your work out into a public forum. I have a few pieces of advice that I hope will help you relax.
1. A professor of mine, a really amazing dude by the name of Beau Carey, gave me some of the best art advice I have ever gotten. Doing something for the first (or even the second, or the fifteenth) time is like making pancakes. The first pancake always comes out all weird shaped and terrible. But it doesn’t stop you from making more, and the more times you pour out the pancake batter, the nicer the pancakes start to look. Inevitably, in your art making career you will have some definite “first pancake” moments. (And some of them will be very public. I’m running my first webcomic ever and I’m definitely having those moments too, haha.) But don’t forget that every pancake you make leads you to making an even neater, prettier one in the future. Acknowledging that your art is always going to be changing and improving (even if it doesn’t feel like it at the time) can help you take the pressure off yourself.
2. The nice thing about posting online is that you can continuously edit your portfolio. I like to just leave my stuff up so that people can see how far I’ve come, but as you make better and better work there’s no shame in taking down the old stuff and putting your best work forward! You have a lot of control over what people will see of your art online, so if it makes you more confident only to show the stuff that you’re still proud of, then do that! Also, there are a ton of options based on which site(s) you post to. Poke around and see what you like!
3. This one is a little more preference-based, but I find that it gives me a lot of peace of mind to watermark or otherwise sign my work. I have one drawing that I did where I only put a subtle watermark on it and now tons of places are ripping it off, making t shirts, etc, and there’s not a whole lot I can do. (Both of the sites I’ve found it on are in Portuguese haha.) Making sure that your work is clearly yours can go a long way towards also making sure that people come back to see more of your stuff, too.
4. Don’t worry if your work doesn’t blow up overnight. I’ve been to a couple of cons now and I’ve been online for a few years, and I’m still pretty much unknown. It takes work to put yourself out there and notoriety rarely happens immediately. Don’t be discouraged!
Anyhow, I hope those things put your mind at ease. If you ever start posting somewhere, I hope that you’ll come off anon and send me a link! I believe in you, stranger! Don’t stop art-ing!