Your parents’ sacrifices are a gift, not a debt. Make something of the gift, and let go of the guilt.

Knowing what somebody gave up for you can turn into a bill you feel permanently behind on, which is almost never what they wanted. A gift given freely cannot be repaid, only used. Guilt makes people cautious and small, which is the worst possible return on what was spent. What was wanted was a good life, not reimbursement.

Use it rather than counting it: do the work, take the chance, build the thing. Tell them once, plainly, that you know what it cost, and let that be enough. If you want to give something back, give them time and news.