<p>Agree with limabeans–your stats are low for most of those UCs. If it makes you feel any better, you would probably have ended up with these same admissions results even if you applied as undeclared. </p>
<p>You could hold off and reapply next year. The SAT II testing requirement goes away for next year’s UC applicants, which would be very helpful for you. But, I don’t know how UC admissions regards students who reapply for freshman status. You’ll need to research that question and find out if UC lets you put in a new freshman (not transfer) application next year. </p>
<p>Another issue is California’s budget problems. Admissions were tightened up this year. for both UC and CSU. Next year could be no change…or more difficult. My crystal ball is hazy. 
Accepting the Merced offer is a bird in the hand; up to you to figure out if you want to take a shot at the two in the bush.</p>