I haven't been playing very long myself, I only reached level 30 a week or two ago. But, I jungle a little bit and have been trying my best to learn the role (I mostly played AP mid when I was leveling to 30). Jungling was the first role that really caught my interest. The first champion I unlocked was Trundle and there was a time where I had my heart set on mastering Trundling. I have a friend who has been playing since LoL's initial release and I asked him for advice on how to start jungling. The advice he gave me is don't invest time into learning to jungle until you reach level 20 and although I didn't really enjoy that advice, I think he was right.
There are champions that can jungle without runes but, they would normally need runes and masteries to improve their ability to clear the jungle quickly and gank effectively such that you can keep up in level. What you will typically find is that you are too far behind in gold and experience to do anything to help your teammates in lane.
Also, you are still learning the game and don't have much experience laning or playing against other players. This is important because a Jungler needs to have a good understanding of what is going on in lane to know best how to help that lane or if they even can for that matter. There are times when there are better ways to help a lane than ganking. There are even times when ganking might end in kill baiting a teammate and not being able to follow up, but to understand that you will need experience in laning.
The other issue with this is that you will be missing out on a lot of fundamental skill developement that applies to every other role. Some examples are: last hitting, poking, trading, baiting and pushing. If you understand these things and when you should be doing them, you will have a strong foundation to learn any of the roles from. But, without these skills or the knowledge to use them, you will have a lot more difficulty with any role you decide to learn.