If I hold to maturity, does it matter if rates rise?

If the issuer repays principal and interest as scheduled, holding to maturity generally secures the yield calculated at the time of purchase.

However, if you suddenly need money and sell partway through, you may incur a loss depending on the price at that time, and you also miss the opportunity to buy bonds paying the now-higher rates. That is why it is important to match the bond's remaining maturity to when you will need the money.