Um. If your age is a problem that is forcing you to lie to your families, what else is there?
I don't want to come across as mean, but this is a very serious, very REAL, undoable situation. If you would lie and say it's an accident, it would lead one to believe you're not really in a position to TTC.
Do you own your own home? Do you live together? How long have you been together? Remember, couples who've been together 20 years still separate.
What about financial needs? In the past three years; have either of you had to borrow money from your parents?
Do you live paycheck to paycheck or are there savings, preferably to the tune of three months' salary? Are both of you complete in your schooling?
What happens if you have a difficult pregnancy, are put on bedrest, and can't work? What will be done for money? And the months after birth when you can't work? What if, god forbid, the baby has medical issues and insurance does not cover the costs? What if one of you loses your job?
Do you have insurance through your parents or through your jobs?
What about daycare? Are you crossing your fingers and hoping your parents will watch the baby, cost-free?
And please don't think this has to do with your age. These are questions EVERYONE should be able to answer prior to TTC, whether 18 or 35.
But the whole statement about saying you plan on telling both sets of parents that this child was an accident is a major red flag.