It is easier to learn to use oil paint or acrylic paint?
Oil paint dries slowly and mixes well on canvas (A thin paint will stick to a thick paint). It also adds texture but shows brush strokes. You are going to want to work in a ventilated area.

Acrylic dries very quickly and dries flat, diminishing brush stroke visibility. Once dried it remains flexible and can be painted over quite easily. When wet it is soluble to water but becomes insoluble once dried.

I recommend acrylic as an introduction as it is easier to work with and is more forgiving. Another solution would be to start with water colors like gouache or aquarelle. These mediums are easier to clean and more portable, but can't be painted over like you can do with acrylic.