NDSolve How do I insert another boundry condition

So I’m new to programming and I am trying to solve a very simple differential equation (i can do this by hand but the thing is i can’t program it), the equation is a'[t] == - 0.0118, with the boundary conditions a[0]==3 and I want to know a[180]=?, how do I insert this (a[180]=?) into the code, this is my short code.

Sol = NDSolve[{a'[t] == -0.0118 , a[0] == 3 }, a, {t, 0, 180}] Plot[Sol, {t, 0, 180}]  

It doesn’t show anything in the plot

Thanks a lot, any type of help will be appreciated