So anyone can be a "disciple", but there were only twelve apostles--those who had firsthand contact with Jesus.
Nope! Remember, Christ said that if our love for Him did not dominate our life then we could not be His disciple:
Now great crowds accompanied him, and he turned and said to them, "If anyone comes to me and does not hate his own father and mother and wife and children and brothers and sisters, yes, and even his own life, he cannot be my disciple. Whoever does not bear his own cross and come after me cannot be my disciple. For which of you, desiring to build a tower, does not first sit down and count the cost, whether he has enough to complete it? Otherwise, when he has laid a foundation and is not able to finish, all who see it begin to mock him, saying, 'This man began to build and was not able to finish.' Or what king, going out to encounter another king in war, will not sit down first and deliberate whether he is able with ten thousand to meet him who comes against him with twenty thousand? And if not, while the other is yet a great way off, he sends a delegation and asks for terms of peace. So therefore, any one of you who does not renounce all that he has cannot be my disciple.
Luke 14:25-33
I think it is often missed that to those to whom Jesus was speaking, ran a very real risk of losing family and possession for simply following Him. The Pharisees, which were against Him, had the ability to kick someone out of the synagogues, while the Saducees, which also hated Him, were the priests and controlled the temple. Following Christ had great ramifications - which was His point.
Count the costs was His message. Unless we love less all that we hold dear now, we cannot follow Him.
There can be no apostles today?
No. Why so? The greek word for apostle,
apostolos means "messenger" or "one sent with orders." This implies a direct communication from the sender. As scripture teaches that scripture is God's completed revelation, then the apostles have no more need. God does not continue to reveal, as the job of these messengers was to relate.