It is not sinful to get married, but married people will have a lot of problems.

1 Corinthians 7:25-28

25 Now I will answer your question about women who have never married. There is nothing that the Lord has commanded me to write about them, but I am writing this to tell you what I think is best, because the Lord Jesus has mercifully enabled me to say what is reliable. 26 There are a lot of distressing events happening now (OR, that will soon happen), so I think that it is better for people to remain in the marital status that they now have. 27 If any of you men are married [RHQ], do not try to divorce your wife. If any of you are unmarried [RHQ], do not seek a wife. 28 But if any of you men get married, you have not committed a sin by doing that. Likewise, if an unmarried woman gets married, she has not committed a sin by doing that. However, those who get married will have many troubles, so I am urging you to remain unmarried in order that you may not experience such troubles.