I have asthma, and a snorkel made it possible for me to get in the pool and swim and swim and swim. If you have any trouble with neck or shoulder pain, the front facing snorkel is very helpful with that as well.
@Kari
Herniated disk checking in; the swim snorkel is a godsend.
Kudos to you for swimming 500 m! That is so awesome!! I use a snorkel all the time I am 59 year old female and simply don’t like getting water in my ears. So I say good for you for using a snorkel! Your future self will thank you for your adaptation!!! 
I have a neck issue and I use a front snorkel all the time.
IMO, anything that helps a person get out and swim, is ok to use.
Snorkel is good to focus on technique. Use the one that is at the front of the face.
Just here to say that this is awesome and keep going!
I almost always train with a snorkel. Only short distances, IMs and then occasionally mid distance. Masters swimmer, but I don’t compete. Yet.
Do what works for you. A snorkel is a great tool and doesn’t inconvenience anyone. After a few months of swimming, maybe give it a go without one, if you’re feeling comfortable. You might be surprised by how much your lung capacity improves with regular swimming. If you still need one, or just like swimming with one more than without, no shame in that either, the important thing is to get in the water and enjoy yourself.
I wish I could use my snorkel 
I breathe through my nose and I can’t get the mechanics behind breathing- with or without a snorkel. I’m doing drills and I’m trying to fix it.
I just started swimming regularly very recently. I use all of the aids I can get my hands on to help me swim. I use a float belt thing and fins because I have issues with floating. I want to use the snorkel so I can concentrate on form, but I’m not there yet.
I’m sure I look silly, but I don’t care. I’m there for me. I’m being active. It feels good and it is great for my mental health. As a happy side effect- I lose weight and gain some lean muscle in the process. Just keep going, however you can do it. Don’t worry about what you think you “should” do. Do what feels good. 
@Lex
Can you wear a nose clip?
I don’t ever swim laps without my snorkel.
Anything is ok! You do what feels good. Working out is about mostly one thing: raising the heart rate. However you do that is fine. Keep at it! Snorkel as much as you want. If you enjoy it, enjoy your time in the water, enjoy making improvements with the snorkel then Just do it!
I see plenty of people practicing with a snorkel to focus on other parts of the technique but you must understand that you are only pushing the real issue away and making things easier. By all means practice with the snorkel but you need to also practice without it. If you are a smoker then stop smoking, use the snorkel every once in a while and work on building your lung capacity back.
Absolutely 100% okay. I have used a snorkel this entire past year that I’ve been swimming and I would not have progressed like I have without it!
I now swim 2mi in 1:07:00 or about 1:57/100yd. I started at 1mi in 1:20:00 and never able to get under 2:20/100yds.
This progress was possible because I didn’t have to focus on breathing AT ALL thanks to the snorkel. I’d still be slow as hell without it.
Snorkels rule! Unless you need to compete where they’re not allowed, there are no downsides to using one for as long as you want.
I’ve been swimming with a snorkel for 14 years. I started when I was 62 1/2. I saw a mile easily using a snorkel. I probably couldn’t swim two laps without one. I don’t see why it makes any difference.
Congratulations on your amazing progress in the pool! However, I would be cautious with snorkel use, given your medical history: https://www.snorkelsafetystudy.com/index.php/faqs/
Would you be able to get some lessons with an instructor or coach who could help you with your breathing and also with some other strokes?
I have improved a lot my breathing since I use a snorkel. I always begin with the snorkel and when I feel the rhythm, I remove it. Swimming with the snorkel helps me to be focused on everything and then I can focus on the breathing. At the end what matters is the workout and the relaxation from swimming. Enjoy.
Yup, I was on a college team, and we always used our snorkels for warm-up and cool down, basically anytime that wasn’t a main set. We used it to really focus on technique without worrying to breathe and break our strokes. Just remember to bring a water bottle bc it will make your throat dry in the long run.
My kid is a college swimmer and part of her required training equipment includes a snorkel. Use it. Don’t feel bad or weird at all.
quitting nicotine finally a few months ago was the best thing I’ve done for myself. I really notice my breathing improving as my lungs heal and I get little bit more capacity back. It makes swimming more challenging, but I’m loving it.