It is very reasonable to conclude the Apostles were Baptized.
28 This took place in Bethany beyond the Jordan, where John was baptizing. 29 The next day he saw Jesus coming toward him, and said, “Behold, the Lamb of God, who takes away the sin of the world! 30 This is he of whom I said, ‘After me comes a man who ranks before me, for he was before me.’ 31 I myself did not know him; but for this I came baptizing with water, that he might be revealed to Israel.” 32 And John bore witness, “I saw the Spirit descend as a dove from heaven, and it remained on him. 33 I myself did not know him; but he who sent me to baptize with water said to me, 'He on whom you see the Spirit descend and remain, this is he who baptizes with the Holy Spirit.’ 34 And I have seen and have borne witness that this is the Son of God.” 35 The next day again John was standing with two of his disciples; 36 and he looked at Jesus as he walked, and said, “Behold, the Lamb of God!” 37 The two disciples heard him say this, and they followed Jesus. 38 Jesus turned, and saw them following, and said to them, “What do you seek?” And they said to him, “Rabbi” (which means Teacher), “where are you staying?” 39 He said to them, “Come and see.” They came and saw where he was staying; and they stayed with him that day, for it was about the tenth hour. 40 One of the two who heard John speak, and followed him, was Andrew, Simon Peter’s brother. 41 He first found his brother Simon, and said to him, “We have found the Messiah” (which means Christ). 42 He brought him to Jesus. Jesus looked at him, and said, “So you are Simon the son of John? You shall be called Cephas” (which means Peter).
This is clearly a shorthand of what happened during this time, it is reasonable to conclude they were Baptized during this time, also as we see in the 3rd Chapter:
3 Jesus answered him, “Truly, truly, I say to you, unless one is born anew, he cannot see the kingdom of God.” 4 Nicode’mus said to him, “How can a man be born when he is old? Can he enter a second time into his mother’s womb and be born?” 5 Jesus answered, "Truly, truly, I say to you, unless one is born of water and the Spirit, he cannot enter the kingdom of God. … 22 After this Jesus and his disciples went into the land of Judea; there he remained with them and baptized. 23 John also was baptizing at Ae’non near Salim, because there was much water there; and people came and were baptized. 24 For John had not yet been put in prison. 25 Now a discussion arose between John’s disciples and a Jew over purifying. 26 And they came to John, and said to him, “Rabbi, he who was with you beyond the Jordan, to whom you bore witness, here he is, baptizing, and all are going to him.” 27 John answered, "No one can receive anything except what is given him from heaven. 28 You yourselves bear me witness, that I said, I am not the Christ, but I have been sent before him. Its does make sense to conclude they were Baptized, else why would the Apostles be Baptizing others? We know that Jesus was Baptized, why not the Apostles?
Later in Acts2:
38 And Peter said to them, "Repent, and be baptized every one of you in the name of Jesus Christ for the forgiveness of your sins; and you shall receive the gift of the Holy Spirit.
Would he have said this if him and the Apostles were not Baptized?
Later in Acts 9:
17 So Anani’as departed and entered the house. And laying his hands on him he said, “Brother Saul, the Lord Jesus who appeared to you on the road by which you came, has sent me that you may regain your sight and be filled with the Holy Spirit.” 18 And immediately something like scales fell from his eyes and he regained his sight. Then he rose and was baptized, 19 and took food and was strengthened.
The first thing Paul did as a Christian was get Baptized.
Next Peter says in 1Pt3:
21 Baptism, which corresponds to this, now saves you, not as a removal of dirt from the body but as an appeal to God for a clear conscience, through the resurrection of Jesus Christ.