After graduating in May, you received a generous $5,000 graduation gift. If you decide to invest this money in the stock market with an assumed interest rate of 8%, how many years would it take for your initial investment to double? Provide a detailed explanation of the calculation process, including any relevant financial formulas or principles used to determine the doubling time in the given scenario. Discuss the implications of the interest rate on the investment growth and any factors that may influence the outcome.