Both of these are fine, in this context.
In broader usage, the word "suitable" tends to refer to the ability of something to perform a task, and how well it can therefore be achieved. "A plumber is the most suitable person to deal with a burst pipe" or "Between a fork and a spoon, the latter is more suitable for drinking soup".
"Appropriate" speaks more to social mores, and appropriateness can be a matter of opinion. "That outfit is not appropriate for a gala ball!" or "You need to have the appropriate tone of voice when talking to elders".
Looking at the antonyms: 'unsuitable' is fairly neutral, whereas 'inappropriate' carries a negative tone.
Please message me if you have any further questions on this nuance. ^_^