Some dogs are great with it, others will always be difficult. I have one of each, but thankfully I don't have to trim nails because they wear them down walking on pavement every day. (I take the cowards' way out
)
Keep practicing with your pup. Be confident and act like it is no big deal -- like they do at the vet's office and groomers. If you are anxious, your pup will sense it.
You could try bringing out the clippers every day and pretend to trim. Just touch her paws lightly without actually trimming. This may help acclimate her to it.
You are a great mom for keeping her nails trimmed. It can be a tough job!