I have created my first D&D5e character and have just achieved level 5.

Race:     Wood Elf

Class:    Fighter

Background:    Soldier

Skills:    Acrobatics and Survival from the fighter class, and Athletics and Intimidation from my background.

When my character reaches 5th level my proficiency bonus increases from +2 to +3.

Do I also increase the proficiency in the two skills gained from my background?