GDScript supports static typing, which you can use to define the type for variables. That said, last I knew the static typing in GDScript allows you to define the variables based on Godot's built in types, so you could define a variable as an integer, but not a uint_8, for example.
This is fairly standard for most dynamic programming languages. One of the pros or cons, depending on how you want to look at it, is that most dynamic languages handle the lower level type definitions so programmers can focus on writing code without needing to worry about what types are being used. The types being automatically handled also can make it easier to port the language, GDScript in this case, to other operating systems.
To answer the question: I guess yes and no. In GDScript you can define variable types in broad terms, but not the specific type. If you want more control over the definitions of the variable types, you might want to look into using C# or C++ with Godot, as both languages offer more control over how variables are defined.
Disclaimer: I am not a Godot developer! Please take what I wrote above with a grain of salt
(Side note: welcome to the forums!)
