My advice- Think long and hard before flying for a living. The guys warning you and trying to dissuade you are all airline guys. Most of them were not that different from you. They all wanted to be pilots living the dream. They are here, and have nothing to gain by warning you off. Consider the source when listening to your flight instructor friends. They have not flown 121. Realize that you are not going to be the same person 10 years down the road. Seeing the world and nailing FA's today, somehow morphs into being stuck in a $hitty hotel alone on Christmas in the midwest tomorrow. Phone calls to your friends about the crazy overnights turn into phone calls to your lonely wife and a 3 year old child you hardly know.
If you fail to heed these warnings, you have no one to blame but yourself. You have been warned.
If that didn't scare you away, well, stick to flight instructing for a while, and hit it hard. Brown-nose around the FBO. Get to know the guys in the hangars. You might luck into a sweet corporate gig. At the very least, you will probably scrounge a few hours in King Airs and Citations. You can probably get a letter of recommendation or two out of it as well. If you do decide to go to a regional, you will be much better off having a firm grasp on basic instrument flying, and a bit more real world experience than 250 hours will give you. You will want to have your radio skills down pat. As a new guy to the 121 world, you will be behind the airplane for a while. Having some solid skills to build on will help tremendously. Good luck in whatever path you choose.