What are the pros and cons of this schema for flashcards app?

I am planning a flashcards app with the following schema:

user(id, name, email)
flashcard_group(id, user_id, group_name, group_tag) 
flashcard(id, group_id, question, solution)
guess(id, user_id, flashcard_id, is_correct)

Some of the things I would like to ultimately calculate are:

• The number of times a user guesses a flash card incorrectly and correctly (or a correctness percentage)

• All of a user's flashcards

• All of the user's flashcard groups

• Probably more information about guesses.

Does this seem reasonable? How else could I go about capturing guesses in a logical fashion?

• Flashcards are used to test knowledge in a topic.

• Each card has a question and a correct answer.

• One topic has many cards.

• Each card may belong to more then one topic.

• User chooses a topic to test in.

• User may attempt the same test many times.

• Each test has many cards (questions) from the chosen topic.

• Each card may be part of many test from the chosen topic.

Note:
UserTopicAttempt is as sequence number (1,2,3 ...) for each (USerID,TopicID).

StackExchange Database Administrators Q#24553, answer score: 4