Can I gift or WILL

My husband owned a flat in his solo name which he had purchased on his own money 20 years ago. He died without any WILL. We have 2 adult children aged 45. I understand that me and my children each inherit 1/3rd of the flat. Now can I further gift my 1/3rd of the flat to any one child ? Am I prohibited by this gift because of the rule of self acquired property vs inherited property ? Someone told me I cannot gift . They said both my children and even grandchildren etc all have rights in my share. Please help with some knowledge