Weight Loss Plateau

I have been the same exact weight for 3 weeks. I have lost 16 pounds total.
Meals are as follows:
Breakfast: one packet plain oatmeal with fresh blueberries added and chia seeds
Lunch: salad with chicken, carrots, tomatoes, bacon, ranch dressing, shredded cheese
Dinner: salad with chicken, avacado, boiled egg, tomato, and avacado dressing
No croutons on the salads.
Water throughout the day and one cup of coffee in the morning.

I have not been working out. Is it time to start?

Any suggestions? Thank you!