Absolutely not. While Aimee will be demonstrating in acrylics, the vast majority of what's taught is foundational to all painting mediums. So, if you wanted to use oils, for instance, you would find all the main principles are totally applicable to you, but there would just be some differences in technique as the mediums have different properties.
But if you're wondering, here are a few reasons you might choose to paint with acrylics!
1. Water Cleanup: Acrylic paints clean up easily with water. You will never need to expose yourself or others to special solvents or thinners when you are using acrylic paints.
2. Fast Drying: I love the fact that I can touch my paintings after a short time and not worry about getting wet paint on myself or what's around me. This makes it much easier to store and transport paintings without all the headache you'd have if they were still wet. Also, when I want to make a change to a painting I can do it quickly.
3. Super Versatile: Acrylic paints can be applied to almost any surface because they adhere so well. They can also be applied very thin and transparent or very thick and impasto-like without having to worry about rules like "thick over thin" because of their quick drying properties. Acrylic paintings are easy to frame because they don't need to be protected with glass.
4. Cost Effective: Acrylic paints are fairly inexpensive when compared to other mediums. This means that you can paint and practice with freedom without being too concerned about cost.
5. Travel Easily: Because they are non-toxic and don't require fancy thinners, you can travel the world with your acrylic paints and never worry about boarding a plane with hazardous materials.