Too late now, but I wish I could get my medical records all the way back to infancy. I recommend that you request a copy of your record -- while you still can -- every time you stop using a provider.
Many providers keep your records for 10 years or less after your last contact. Most will want to keep your record for at least 3 years (after your age 18 for kids) for potential use in defending a malpractice suit. You can keep your own records indefinitely. You can also review them for errors before passing them on to a new provider.