Hi
Unless you choose to keep your avocado in a patio pot and keep it pruned to a manageable size, you may want to rethink this idea. If it is a Florida variety, it will grow 30 to 60 ft. tall eventually. Floridata (helpful website!) also adds:
"Planting distances depend on soil type and fertility, current technology, and expertise of the homeowner. Avocado trees in the home landscape should be planted 23 to 30 feet or more (7.0 to 9.1 m) away from buildings and other trees. Trees planted too close to other trees or structures may not grow normally or produce much fruit due to shading."
Hope that helps you!