Erik, the reason I love this hobby so much is that it can be whatever you want it to be. I think it is fair to say that nearly all of us here at the castle, and on other forums, all started as young collectors. We all had limited resources and finances for our collecting. But that is a great thing, not something to be sad about. If you had all the money in the world, if you could buy any coin you wanted right from day one, where would the appreciation of the hobby be? The easier it is to obtain something, the less we treasure and respect it.
It may be hard for you at the moment, but do you look at any of the coins you have and say, that doesn't mean anything to me, if it was gone, who cares? As you said in your post, you have coins you have received from members here that you treasure, not just because it is a nice coin, but also because someone thought of you and went to the trouble of sending it to you. You are sad because sometimes your packages don't arrive. This has happened to all of us, and it feels just as bad for the person sending the coins, perhaps mors so, because the act of giving feels better than receiving. If I send someone something and it doesn't arrive, I feel terrible for days and days.
When I was young, all I could collect were coins from circulation, and only from my own country. There was no internet to be able to trade with people for foreign coins. I lived in the bush, with no city or town anywhere near to be able to buy coins from even if I did have money.
So I was happy just searching and looking through my parents change, looking for dates I didn't have, or trying to improve on the quality of what I had. It wasn't untill I got a part time job that I could actually start to buy coins.
As I have grown older, I have become quite successful in business and am now in the position where I can buy the coins I like. And it can be very expensive. But do you know what I have the most fun collecting, and what I like the most? Putting together collections from circulation. Cheap, dirty, worn coins that have seen so much in their little metal lives. It takes time, true, and at times it is frustrating when you can't find a coin you are looking for, but that is all part of the fun.
If you give away the hobby now, just because your collection isn't growing as fast as you would like, you will never be happy. It is the way with all things that are worthwhile, they take time to develop and grow into something wonderful. Not one of us here can collect as fast as we want to, it is not possible. If we were, we would still want more.
Don't think of what you don't have, think of what you do have. Don't think you can't get coins, think of ways to get them. Don't worry that the postman lost your package, he has done it to all of us. Don't think you are too young, you are not. Don't think it is an expensive hobby, it doesn't have to be.
And don't stop being a collector just because right now it isn't working out the way you want. I can think of things right now that you could be doing to improve and add to your collection. But, like I said above, good things only happen with a little effort, so if you want me to tell you, you have to promise to stick around here and keep collecting. It is up to you.