better wait till the 2nd or 3rd heat. Your dog has not fully matured mentally and physically at the age of the 1st heat. Considering a dalmatian is a fairly large dog, they mature at a later age compared to small breeds. But regardless of the size of the dog, it is common and wise practice to wait till the later heat and let the 1st heat pass.
as for "masugpo ang tubo", i don't know about that but consequences of too early whelping in dams are abandonment of puppies, congenital problems, cannibalism (eating their own pups), puppy rejection etc. Although there are successful whelpings even in very young dams, as their owner, you would know naman what's best.
