Repentance for neglecting prayer
Question

                I am 38 years old man. till the age of 25 I
      did'nt prayed. please advice me what I have to do for this?
Praise be to Allah.Remember how Allaah has blessed you by bringing 
  you back to Islam after you have been neglecting salaah, and keep on doing the 
  prayers at the right times. Do more naafil (supererogatory or extra) prayers 
  to make up for the fard (obligatory) prayers that you have missed, as was advised 
  in the saheeh hadeeth narrated by Hurayth ibn Qubaysah, who said: I came 
  to Madeenah and prayed, O Allaah, send me a righteous companion. 
  I went and sat with Abu Hurayrah and said: I asked Allaah to bless me 
  with a righteous companion; tell me a hadeeth that you heard from the Messenger 
  of Allaah  (peace and blessings of Allaah be upon 
  him), so that I may benefit therefrom. He said: I heard the Messenger 
  of Allaah  (peace and blessings of Allaah be upon 
  him) say that the first thing for which a person will be brought to account 
  on the Day of Resurrection will be his prayer. If it is sound, he will be successful, 
  and if it is lacking in any way, he will be doomed. If his obligatory prayers 
  are lacking, the Lord will say: Look and see whether My slave has any 
  voluntary prayers which may be used to make up what is lacking in his obligatory 
  prayers. Then all his deeds will be examined and dealt with in the same 
  way. (Reported by al-Tirmidhi, no. 413; see 
  also Saheeh al-Jaami, 2020). 
  Abu Dawood reported from Anas ibn Hakeem al-Dabbi that he came to Madeenah and 
  met Abu Hurayrah. He said: He asked me about my lineage so I told him 
  about it, then he said: O young man, shall I not tell you a hadeeth? 
  I said, Of course, may Allaah have mercy on you, and I think he 
  mentioned it from the Prophet  (peace and blessings 
  of Allaah be upon him). He said: The first thing that people will be asked 
  about on the Day of Resurrection will be their prayers. Our Lord will say to 
  His angels (although He knows best): Look at My slaves prayers: 
  are they complete or is something lacking? If they are complete, they 
  will be recorded as such, but if something is lacking, He will say: Look 
  and see if My slave has any voluntary prayers to his credit. If this proves 
  to be the case, He will say: Make up his (missing) obligatory prayers 
  with his voluntary prayers. Then the rest of his deeds will be dealt with 
  in the same manner. (Saheeh al-Jaami, 2571)