Decisions are based on priorities, whether implicitly or explicitly. Trusting yourself enough to make decisions that align with who you are at the core is a skill learned over time. Much like swimming or surfing or studying or any other practice, the more you do it the better you get. Life is like that; this is natural law: investing your time into a skill increases your level of experience, which will imply progress where you choose to invest.
I read once, or twice, from Warren Buffett that there's an activity you can do to figure what it is you really want to do in life. Warren Buffett suggests the following: write down twenty things you want to do in your life, then cross out the bottom fifteen and never pursue them again, then pursue the top five with all your heart.
The best part of the lifelong decision process is that life is about learning lessons anyhow, so when making decisions that don't align with priorities, or if priorities change, there's learning that comes from that, and then reflection will allow us to make the necessary changes in our thinking process and keep rolling.
Over time with this process, we gain experience, whether from talking to others, reading or actively participating in your own life. The more experience we have the easier it gets to decide on what we want. This way you can become a valuable contributor to your self, family, community and world.
"The most difficult thing is the decision to act, the rest is merely tenacity. The fears are paper tigers. You can do anything you decide to do. You can act to change and control your life; and the procedure, the process is its own reward." - Amelia Earhart
The hard part is deciding. The action can be difficult as well, but I've found it's easier to do than to choose. Mostly because there's so much to do! Usually our heads are swimming with thousands of different ideas based on what other people have thought we ought to do. The best thing to do is to unapologetically be you!