There are no tax "penalties" for withdrawing money from an investment account. This is because investment accounts do not receive the same tax-sheltered treatment as retirement accounts like an IRA or a 403(b). There are also no age restrictions on when you can withdraw from your investment account.
However, when you withdraw from your investment account, you may have to pay capital gains taxes if your funds earned money. If you decide to withdraw, GuideStone will issue you a 1099 form before the tax deadline to use for tax filing.