It would seem you are being overly ambitious.
According to this link at PBS:
Some children at the beginning of this year are still learning how to
verbally count by ones up to "ten." The average five-year-old,
however, will be able to use the "teen" pattern to accurately count to
"20." (Some children may not be able to count up to "20" until age
six.) Other children will be able to use repeating patterns to
accurately count up to "42," with the average child able to do this by
the second half of this year. (Some children may not be able to count
up to "42" until age six.) In the second half of this year, a few
five-year-olds will be able to use repeating patterns to accurately
count up to "200." (The average child can count to "200" at age six.)
This refers to counting. Actually understanding and using the numbers at this age:
At age five, some children may still be gaining an understanding of
the number words up to "four" (e.g., distinguishes one-four items from
"many"; can identify collections of up to four items with a
corresponding number; asks for up to "four" of something; knows age;
can put out "one," "two," "three," or "four" items upon request).
Although there are gifted children - it is not clear what value there is teaching the child something s/he is not ready for if it is not expected for children of this age.
There is lot more information at the link. There is additional information for children of other ages and for other subjects.
I used this link because it is geared for parents and the teachers at my school find it useful and accurate.