Hi and welcome to the site.

Are you enrolled in the Fundamentals 1 class? If not and your new to guitar you should be.

The instructor will teach proper fretting for every chord and a little exercise you can do before each practice called Spider Legs. This will help with finger strength and dexterity. It's like stretching before going to the gym. You'll be doing it for most of your guitar life. Even the instructor does it. It's all part of the learning curve. Your fingers are doing something they never did before. Take it slow even if you just have to form one part of the chord for now like using only one or two fingers. Sooner than you expected that third finger will get there.

Good Luck,

Moe