You can successfully learn another language.
What does a child language learner know about language learning that enables him to successfully learn a language virtually on his own?
Successful language learners — both children and adults — begin with an underlying knowledge that a language is learned rather than taught. And they know how to take advantage of the abundant resources available to them. These resources are the people who speak the language.
In general, successful language learners learn a little and use it a lot. They get what they need, and practice it, and then use it in actual communication with people. They also spend time in reflection — consolidating their gains and identifying new felt needs — which in turn leads them to get and practice more material which is then also used. You were once a child and this is the way you learned your first language.
Brewsters, Language Acquisition Made Practical