When you first start with REs it looks like the difficulty is in learning the meta-language. Actually that is the easy part, the most difficult part of using REs is in understanding your data.
For example, "samir: 23 yearold". Is the name always at the start of text and preceeded by a colon ':'? Is there always a space before and after the age? Is the age always 2 characters, or between 1 and 3 digits? And so on.
To extract text from an RE you can use a "capturing parenthesis group", which just means that the pattern described in rounded brackets are saved into special variables, the first going into $1, second into $2, and so on. I suggest you go through
perlretut.
There are many solutions to your question, mine would be:
my $s = 'samir: 23 yearold';
$s =~ /^(.*: \d+)/;
my $NameAge = $1;
print "$NameAge\n";