What do you mean by assuming a woman you see is "better off than you"? Are you talking about financially? If so, that's nothing to worry too much about. Women are attracted to men who make them feel a certain way. Money CAN be a part of that but it's not a very important part. Plenty of unemployed and homeless guys are sleeping with many women.
Being a late-bloomer is a curse in your younger years but it will be a huge benefit later in life. That being said, you can still do fine while looking young but you will have the best luck with women who are in the late teens. It can also help to make yourself appear less boyish - you can do this by the way you dress, style your hair, and also by growing facial hair. I would strongly encourage all that.
What is your concern about a woman being older than you? If YOU think she is attractive and you would sleep with her, what's the problem with her age?
You are doing the right thing by practicing approaches. You have to get over your fear. If you are really struggling with it, as it sounds that you are, start out by talking with women you don't find attractive and who you suspect might be chatty... think moms who have their kids with them or old ladies. This can be done in line at the store, etc. Best places are places where you are stuck standing in line or doing something like shopping. The FIRST thing you must learn is that women are open to talking to strangers and they actually like to 9x out of 10. Women are more social than men. Many men just want to be left alone and not bothered as they go about their day but women LOVE talking. Some women have bad social anxiety but again, on average, most women are much more social than men and much happier than men to have a casual conversation with a stranger. So just ask the old lady next to you how to know if an avocado is ripe while standing next to her at the avocado bin. Or if you are buying a new shirt and there is a girl nearby, ask her what she thinks of it by saying you'd like to get a woman's opinion. Don't have any romantic intentions in any of the conversations. Plan to start and end the interaction with platonic idle chit-chat only. Once your brainwashing about women not wanting to talk to strangers has been eased, you can start approaching attractive women for platonic conversations. Then you can move up from there by going in with romantic intent and getting phone numbers after talking with a girl for a while.
I think workshops can be beneficial to guys who are REALLY struggling to get past a crippling fear of approaching women, but there are so many guys who run these workshops and I've cringed at what I've seen on youtube from many (but not all) of them. If you need help forcing yourself to approach, find a buddy you trust who wants to do the same thing as you and hold each other accountable. Go out together and do approaches - one approaches while the other watches from a distance. Then switch turns. The pressure of having someone with you and pointing out girls to approach might really help you. You can make a game out of it by "can't say no" and whoever your friend points to, you HAVE to approach no matter what the situation is, and same for him.