As an introvert, I anticipated spending a weekend in a house with ten strangers with fear and loathing, but it turned out to be a memorable and enriching experience.
If you worry about being a good friend, choose the people you love and trust most and tell them how you feel. This simple act will bring you closer together.
Labeling yourself "an introvert" suggests a fixed behavior hewing to a set of guidelines; considering yourself "introverted" is a starting point for self-discovery.
Introverts are good listeners, but do we even try to get our fair share of the conversation, or simply allow our needs to be buried under other people's chatter?
Introverts often ask me if their choices are weird, but the only way to answer that question is to figure out if you are getting what you want from your life and relationships.
If you have trouble expressing your needs it's not necessarily because you're an introvert, but some introverted behaviors might contribute to the problem.
You might not need a lot of friends and you might not need to see them often, but you do need friends. Introversion is no excuse--or reason--for letting friendships lapse.