Makeup help

Sam • Yep.
I need some major help with makeup! 
I'm 16, but I look 12! I've been told that my whole life I look really young for my age.  Now every time I get dressed up really nice with makeup on, I look a lot older. 
So, 
Every  time I need to wear makeup (besides mascara) I just pay to get it done. I literally have no idea what I need to use to look "good." I'm tired of going around places with my boyfriend and people assuming I'm his little sister because I look so young! 
If you could please tell me what kind of stuff you use that works good, and what you recommend me using that would be amazing!
I just really need some help since I'm a junior in high school and I'm like one of the only girls who just wear mascara everyday. :( 
Please don't judge. 
Me yesterday without makeup.
Me wearing just mascara. 
Me wearing mascara and eyeliner. I also did my eyebrows, sorta..
Me in April getting ready for my sisters wedding. A lot of makeup. 
(Sorry the pictures are bad. these are literally the only ones I have of me wearing a lot of makeup.) I showed you  pictures of me wearing different amounts of makeup to show you I have no idea what I'm doing! Help please!