Praise be to Allah.wa aliaikum us-salaam wa-rahmat ullaahi wa-barakaatuh.
(a) Jumhoor al-ulemaa' (vast majority of the scholars) agree that the aqeeqa is a sunnah mustahabbah for those who are capable of doing it and can afford it. Among its benefits are breaking the influence of the shaitaan on the new-born. It is also permissible for a Muslim to make an aqeeqah for himself if his parents did not perform it for him. Similarly, he can do it for his children even if it is after many years if he didn't do it when they were young.
Refer to the book "Tuhfat ul-Mawdood bi-Ahkaam il-Mawlood" by Imam Ibn ul-Qayyim, Chapter 6: "The Aqeeqah and its Rulings", Part 19: "The Ruling for One Whose Parents Did Not Perform an Aqeeqah--Should He Perform one on His Own Behalf?" for more details. It is mentioned there that Ismaa'il ibn Sa'eed al-Shaalanji asked (Imam) Ahmed regarding a man whose father informed him that he did not perform an aqeeqah on his behalf--should he perform it on his own behalf? He said,
"That is the father's duty." ...
and it was said, "Should one perform an aqeeqah on his own behalf as an adult?" ... and I saw that it is preferrable if an aqeeqah was not performed as a child then it should be performed as an adult, and (Imam Ahmed) said:
"If someone does that I would not discourage it or regard it as reprehensible."
(b) It is not mandatory for a person to take a loan in order to spend on an aqeeqah. However, if he does it then it would be considered commendable as per Imam Ahmed's opinion. It was related by Abi il-Harith that he asked Abu Abdullah regarding one who doesn't have enough to perform an aqeeqah; Imam Ahmed said,
"If he borrowed for it I hope Allaah would reward and provide for him by virtue that he has observed a sunnah."
Refer to "Tuhfat il-Mawdood," same chapter, Part 11: "Regarding Borrowing for an Aqeeqah and its Rulings and Benefits."